Advertisement
JBC

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]


     


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a Letter to Editor
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowRequest Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lali, F. V.
Right arrow Articles by Foxwell, B. M. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lali, F. V.
Right arrow Articles by Foxwell, B. M. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?

J Biol Chem, Vol. 275, Issue 10, 7395-7402, March 10, 2000


The Pyridinyl Imidazole Inhibitor SB203580 Blocks Phosphoinositide-dependent Protein Kinase Activity, Protein Kinase B Phosphorylation, and Retinoblastoma Hyperphosphorylation in Interleukin-2-stimulated T Cells Independently of p38 Mitogen-activated Protein Kinase*

Ferdinand V. LaliDagger , Abigail E. Hunt, Sarah J. Turner, and Brian M. J. Foxwell§

From the Kennedy Institute of Rheumatology, London W6 8LH, United Kingdom

    ABSTRACT
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

Pyridinyl imidazole inhibitors, particularly SB203580, have been widely used to elucidate the roles of p38 mitogen-activated protein (MAP) kinase (p38/HOG/SAPKII) in a wide array of biological systems. Studies by this group and others have shown that SB203580 can have antiproliferative activity on cytokine-activated lymphocytes. However, we recently reported that the antiproliferative effects of SB203580 were unrelated to p38 MAP kinase activity. This present study now shows that SB203580 can inhibit the key cell cycle event of retinoblastoma protein phosphorylation in interleukin-2-stimulated T cells. Studies on the proximal regulator of this event, the phosphatidylinositol 3-kinase/protein kinase B (PKB)(Akt/Rac) kinase pathway, showed that SB203580 blocked the phosphorylation and activation of PKB by inhibiting the PKB kinase, phosphoinositide-dependent protein kinase 1. The concentrations of SB203580 required to block PKB phosphorylation (IC50 3-5 µM) are only approximately 10-fold higher than those required to inhibit p38 MAP kinase (IC50 0.3-0.5 µM). These data define a new activity for this drug and would suggest that extreme caution should be taken when interpreting data where SB203580 has been used at concentrations above 1-2 µM.

    INTRODUCTION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

Interleukin-2 (IL-2)1 is a potent T cell growth factor that mediates its effects via a high affinity heterotrimeric receptor comprising alpha , beta , and gamma c subunits. Several intracellular signaling pathways are known to be activated by IL-2, including the p42/44 mitogen-activated protein kinase (MAP kinase, also known as ERK2/1), the p38 and p54 MAP kinases (also called stress kinases, or HOG and JNK, respectively), the phosphatidyl inositol 3' (PI) 3-kinase pathway and the Jak/STAT (signal transducer and activator of transcription) pathways. Our earlier studies using the MEK (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase) inhibitor PD098059 (1) and those of others (2, 3) have indicated that the p42/44 MAP kinase pathway is not required for IL-2-driven proliferation. In contrast, a pyridinyl imidazole inhibitor of p38 MAP kinase, SB203580, inhibited IL-2-driven T cell proliferation with an IC50 of 3-5 µM, suggesting a possible role for p38 MAP kinase in this process (4). Recently, we have further investigated the role of p38 MAP kinase in proliferation by mapping the subdomains of the IL-2 receptor beta  chain involved in the activation of the kinase. As previously shown for p42/44 MAP kinase, activation of p38 and p54 MAP kinases required the acidic rich A region of the IL-2 receptor beta  chain (5). However, the A region is not required for proliferation (2, 5), indicating that neither p38 MAP kinase nor p54 MAP kinase is essential for this function. Furthermore, CNI-1493 (6, 7), an inhibitor of p38 and p54 MAP kinase activation by IL-2 was unable to inhibit proliferation (5). Surprisingly, SB203580 was still able to inhibit proliferation in the absence of IL-2 stimulated p38 MAP kinase activation. It has already been reported that SB203580 does inhibit p54 MAP kinase activity (8, 9), but the possibility that the anti-proliferative effects of SB203580 may be mediated by effects on p54 MAP kinase can also be discounted by the studies of Hunt et al. (5).

The above data suggest the existence of a novel target of SB203580 that is critical for mitogenic signaling. To help understand the mechanism of action and possible targets of SB203580, the effect of this inhibitor on cell cycle-regulated proteins was examined. We found that the IL-2-induced hyperphosphorylation of Rb was greatly reduced in SB203580-treated cells, whereas the drug had no effect on cytokine-induced p27kip degradation or Myc expression. Subsequent studies investigated the effects of SB203580 on PI 3-kinase/protein kinase B (PKB), as these kinases have been implicated in the regulation of Rb phosphorylation (10). We observed that although PI 3-kinase activity was unaffected, the phosphorylation of PKB on Thr308 and Ser473 was inhibited, resulting in an inhibition of IL-2-induced kinase activity. The concentrations of SB203580 required were commensurate with antiproliferative effects of the drug and provide evidence that 3-phosphoinositide-dependent protein kinase 1 (PDK1; the Thr308 kinase) is inhibited by SB203580. It has recently been reported that PDK1 also acts as the Ser473 kinase (11). These results could provide a mechanism for the antiproliferative effect of SB203580. Furthermore these data will have important implications for the interpretation of results from numerous published studies in which SB203580 has been used at concentrations in excess of 2 µM.

    EXPERIMENTAL PROCEDURES
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

Materials

IL-2 was a generous gift from Dr. P. Lomedico (Roche Molecular Biochemicals). Antiphospho-specific Ser473 and Thr308 PKB were from New England Biolabs (Hitchin, Herts, UK), whereas sheep anti-PKB and other reagents for in vitro PKB kinase assay were sold as a kit by Upstate Biotechnology, Inc. (Lake Placid, NY). Anti-Rb was from Pharmingen (San Diego, CA), and the monoclonal anti-cyclin D3 and anti-p27kip1 were from Pierce. Rabbit anti-p70S6 kinase was from Santa Cruz Biotechnology, Inc. (Santa Cruz, CA) and was used for both immunoprecipitation and Western blotting. Rabbit anti-c-Myc antibody was from Santa Cruz (Santa Cruz, CA). SB203580 was purchased from Calbiochem-Novabiochem, and U5 anti-p85alpha monoclonal antibody was a generous gift from Professor D. Cantrell (Imperial Cancer Research Fund, London). Rabbit antisera to p38 MAP kinase was from Professor J. Saklatvala (Kennedy Institute of Rheumatology, London). Second-layer antibodies (horseradish peroxidase-conjugated) were purchased from DAKO (DAKO A/S Denmark). Recombinant PDK1 and recombinant PKB were kindly provided by Dr. L. Stephens (Babraham Institute, Cambridge, UK) and Dr. D. Alessi (Dundee, UK). CN1-1493 was from Dr. K. Tracey (Picower Institute of Medical Research New York).

Methods

Cells and Proliferation Assay The IL-2-dependent murine T cell line, CT6, was grown and maintained as described previously (12). These cells were rested by washing three times in RPMI and culturing overnight in RPMI, 5% fetal calf serum in the absence of growth factor, antibiotics, or beta -mercaptoethanol supplements. 2-5 × 106 rested CT6 cells were resuspended in 2 ml of RPMI, 5% fetal calf serum and preincubated with inhibitors or vehicle control as indicated in figure legends. Cells were then stimulated with 20 ng/ml recombinant human IL-2 for 5 min at 37 °C and pelleted in a minifuge for 30 s, medium was aspirated, and the pellet was lysed in the appropriate buffer. BA/F3 cells stably expressing deletion mutants of IL-2 receptor beta  chain (a generous gift from Professor T. Taniguchi, Tokyo, Japan) were maintained in glutamine containing RPMI further supplemented with 5% fetal calf serum and 0.2 µg/ml G418 (Calbiochem-Novabiochem) as described previously (13). Human peripheral blood mononuclear cells were prepared from buffy coat leukophoresis residues (North London Blood Transfusion Service, Colindale, London UK) and activated with 50 ng/ml OKT3 for 48 h. The cells were then washed extensively, rested overnight, and washed again before activating with IL-2; such cell preparations were >90% T cells (14). Cellular proliferation assays were performed by measurement of [3H]thymidine incorporation as described previously (12).

Kinase Assays

PKB Kinase Assay-- Cells were lysed in Buffer A (see below) for Western blotting and PKB kinase assays. Kinase assays were performed according to the manufacturer's instructions. Briefly, 4 µg of sheep anti-PKBalpha was immobilized on 25 µl of protein G-Sepharose overnight (or 1.5 h) and washed in Buffer A (50 mM Tris, pH 7.5, 1 mM EDTA, 1 mM EGTA, 0.5 mM Na3VO4, 0.1% beta -mercaptoethanol, 1% Triton X-100, 50 mM sodium fluoride, 5 mM sodium pyrophosphate, 0.1 mM phenylmethylsulfonyl fluoride, 1 µg/ml aprotinin, pepstatin, leupeptin, and 1 µM microcystin). The immobilized anti-PKB was then incubated with 0.5 ml of lysate (from 5 × 106 cells) for 1.5 h and washed three times in 0.5 ml of Buffer A supplemented with 0.5 M NaCl, two times in 0.5 ml of Buffer B (50 mM Tris-HCl, pH 7.5, 0.03% (w/v) Brij-35, 0.1 mM EGTA, and 0.1% beta -mercaptoethanol), and twice with 100 µl of assay dilution buffer; 5× assay dilution buffer is 100 mM MOPS, pH 7.2, 125 mM beta -glycerophosphate, 25 mM EGTA, 5 mM sodium orthovanadate, 5 mM DTT. To the PKB enzyme immune complex was added 10 µl of assay dilution buffer, 40 µM protein kinase A inhibitor peptide, 100 µM PKB-specific substrate peptide, and 10 µCi of [gamma -32P]ATP, all made up in assay dilution buffer. The reaction was incubated for 20 min at room temperature with shaking, then samples were pulse spun, and 40 µl of reaction volume were removed into another tube to which was added 20 µl of 40% trichloroacetic acid to stop the reaction. This was mixed and incubated for 5 min at room temperature, and 40 µl was transferred onto P81 phosphocellulose paper and allowed to bind for 30 s. The P81 pieces were washed three times in 0.75% phosphoric acid then in acetone at room temperature. gamma -32P incorporation was then measured by scintillation counting.

PI 3-Kinase Assay-- Cells were lysed in PI 3-kinase lysis buffer (40 mM Tris-HCl, pH 7.5, 200 mM NaCl, 1 mM EGTA supplemented with 1 mM DTT, 1 mM Na3VO4, and 10 µg/ml each of aprotinin, pepstatin, leupeptin) at 10 × 106 cells/ml, and the post-nuclear lysate was precleared with 25 µl of protein G-Sepharose for 1 h then preincubated with 5 µg of monoclonal anti-p85alpha (U5) and further with 25 µl of protein G-Sepharose for the final 1 h. The pellets were washed three times in 0.5 ml of PI 3-kinase assay buffer. The pellet was then resuspended in 25 µl of kinase assay buffer. To this, 10 µl of a 1 mg/ml mixture of phosphatidylinositol and phosphatidylserine (made up in 100 mM HEPES, pH 7.5, and sonicated just before use) was added. The mixture was then preincubated at room temperature for 10 min, and the reaction was started by the addition of 15 µl of ATP mixture (340 µl of water, 4.2 µl of 1 M MgCl2, 16 µl of 100 mM ATP) supplemented with 5 µCi of [gamma -32P]ATP. The reaction proceeded for 15 min and was stopped by the addition of 100 µl of 1 M HCl and vortexing, adding a further 200 µl of a 1:1 chloroform:methanol and vortexing again, and microfuge-spinning the tubes for 5 min. The lower layer was removed and dried in vacuo (or at 60 °C on dry block) then redissolved in 10 µl of 4:1 chloroform:methanol before spotting onto silica plates. The plate was developed in a preequilibrated vertical tank with chloroform, methanol, 28% ammonium hydroxide, water (180:140:10.8:27.5) for 3 h (or overnight) followed by phosphorimaging analysis (Fuji FLA-2000).

p70S6 Kinase Assay-- Cells were lysed in 0.5 ml of p70S6 kinase lysis buffer (10 mM potassium phosphate, pH 7.05, 0.5% Triton X-100, 1 mM EDTA, 5 mM EGTA, 1 mM Na3VO4, 1 mM phenylmethylsulfonyl fluoride, 10 µg/ml leupeptin, 1 µg/ml pepstatin, 1 µg/ml aprotinin), and the postnuclear lysate was precleared with 20 µl of protein A-agarose for 30 min. The precleared supernatant was then preincubated with 5 µl of rabbit antiserum to p70S6 kinase for 1 h and additionally with 25 µl of protein A-agarose with mixing for a further 1 h, all at 4 °C. The final immune complex was washed twice in 0.5 ml of lysis buffer and twice in 0.5 ml of kinase assay buffer (50 mM MOPS, pH 7.2, 1 mM DTT, 30 mM ATP, 5 mM MgCl2, 10 mM p-nitrophenylphosphate). To washed immune complex pellet was added 45 µl of assay mixture (made up of 35 µl of kinase assay buffer, 5 µl of 125 mM substrate peptide (KKRNRTLTK), 5 µl of 50 µM protein kinase A inhibitor, 5 µCi of [gamma -32P]ATP), and the reaction was allowed to continue for 30 min at room temperature. The reaction was stopped by the addition of reducing sample buffer and boiling for 5 min. After separation on a peptide gel as described before (15), radioactivity incorporated into peptide was quantitated by phosphorimaging.

Recombinant PDK1/PKB Assays-- Lipid vesicles were made by drying down a mixture of phosphatidylcholine and phosphatidylserine in vacuo and reconstituting with lipid buffer (0.2 M NaCl, 20 mM HEPES, 2 mM EGTA) to a final 5 times working stock (500 µM phosphatidylcholine, 500 µM phosphatidylserine, and 100 µM phosphatidylinositol 3,4,5-trisphosphate (PIP3) and sonicated before use. EE-tagged recombinant PDK1 and PKBalpha (both >98% pure) were prediluted in enzyme dilution buffer (1 mM DTT, 0.1 M NaCl, 1 mM EGTA, 20 mM HEPES). PDK1 assays were performed with 1 µM EE-PKB and 50 nM EE-PDK1 in the presence of appropriately diluted lipid vesicles, 0.5 µM ATP, and 1 µCi of [gamma -32P]ATP in assay buffer (8 mM MgCl2, 0.12 M NaCl, 1.2 mM DTT, 1.2 mM EGTA, 0.01% azide) supplemented with protease inhibitors (1 mM phenylmethylsulfonyl fluoride, 10 µg/ml aprotinin, 10 µg/ml leupeptin) in a final volume of 5 µl. The reaction was allowed to continue for 5 min at 30 °C and stopped by boiling with 10 µl of 1.5 times SDS sample buffer (with 5 mM EDTA). The PKB autokinase assays were performed as above for PDK1 but in the absence of PDK1 and PIP3. Samples were then resolved on a 10% SDS-polyacrylamide electrophoresis gel and quantitated by phosphorimaging (Fuji FLA-2000).

Western Blotting-- After separation by SDS-polyacrylamide gel electrophoresis, proteins were transferred onto nitrocellulose or polyvinylidene difluoride membranes that were then blocked with 5% (w/v) milk powder in Tris-buffered saline/Tween 20 (0.1%) for 1 h at room temperature. The blocked membranes were then incubated in 1:1000 dilution of first-stage antibody (made up in Tris-buffered saline Tween, 2% bovine serum albumin supplemented with 0.1% azide) overnight, then washed and incubated with 1:1000 horseradish peroxidase-conjugated secondary antibody (made up in Tris-buffered saline Tween, 5% (w/v) milk powder) for 1 h at room temperature before developing with ECL.

    RESULTS
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

SB203580 Inhibits IL-2-induced Rb Hyperphosphorylation-- As we have shown previously (4, 5), the IL-2-induced proliferation of primary human T cells, murine CT6 T cells, or BAF F7 B cells is prevented by the p38 MAP kinase inhibitor with an IC50 of 3-5 µM (Fig. 1). However, as our recent studies (5) showed that IL-2-induced proliferation and the inhibitory effects of SB203580 on this event were independent of p38 MAP kinase or even p54 MAP kinase activity in both T cells and B cells, we endeavored to identify other possible targets involved in mediating the anti-proliferative effects. To do this, we investigated events associated with cell cycle progression. SB203580 had no effect on Myc expression, except for a small reduction at 30 µM only (Fig. 2a). Furthermore, nuclear staining of SB203580-treated CT6 cells with propidium iodide showed no evidence of apoptosis after stimulation with IL-2 for 20 h (data not shown). The expression of hyperphosphorylated Rb and degradation of p27kip1 were also measured as markers of S-phase entry. The addition of IL-2 to resting CT6 cells caused the hyperphosphorylation of Rb as detected by Western blotting (Fig. 2b). The presence of SB203580 in the antiproliferative (0-30 µM) range resulted in a dose-dependent reduction in the hyperphosphorylated form (Fig. 2b). There also appeared to be some reduction in the total levels of Rb protein. Similar inhibitory effects on Rb hyperphosphorylation and protein levels were obtained with wortmannin and LY294002, both inhibitors of PI 3-kinase. The decrease in Rb protein is likely to be due to the IL-1-converting enzyme (ICE)-mediated proteolysis of the hypophosphorylated form, which has been previously reported (16-18). These results would also agree with previous studies on the role of PI 3-kinase in IL-2-induced Rb hyperphosphorylation and protein by Brennan et al. (10) and would support previous indications that PI 3-kinase is a proximal regulator of Rb (10, 19, 20). The effects of SB203580 on Rb hyperphosphorylation were confirmed in similar studies on activated primary human T cells (Fig. 2d).


View larger version (16K):
[in this window]
[in a new window]
 
Fig. 1.   Effect of SB203580 on IL-2-induced proliferation. Effect of SB203580 on the proliferation of CT6 (diamonds), BA/F3 cell line F7 (squares), and PBMC/T cells (circles). Rested cells were preincubated with 0-30 µM SB203580 or vehicle control for 1 h and cultured for 24 h in the presence of 20 ng/ml IL-2. 0.5 µCi/well of [3H]thymidine was added for the last 6 h. Thymidine incorporation was measured by scintillation counting, and the data points are expressed as the mean of triplicate measurements ± S.E. The data show [3H]thymidine incorporation as a percentage of [3H]thymidine incorporated into cells without inhibitor. The average IL-2-induced thymidine incorporation (cpm ± S.E.) for the different cell lines were 166,977 ± 7,465 for CT6 cells, 93,219 ± 3,537 for PBMCs, and 130,571 ± 661 for the BA/F3 F7 cells. Data are representative of at least three separate experiments.


View larger version (35K):
[in this window]
[in a new window]
 
Fig. 2.   Effect of SB203580 on cell cycle proteins. Resting CT6 cells (a, b, c) and PBMC (d and e) were preincubated with the indicated doses of SB203580, wortmannin, LY294002, or vehicle control for 1 h before stimulating with 20 ng/ml IL-2 or vehicle control for 3 h (c-Myc) or 20 h (Rb and p27kip). Cells were then lysed and prepared for total cellular c-Myc (a) Rb (b and d) or p27kip (c and e) measurement by Western blotting as described under "Experimental Procedures." The data are representative of three separate experiments. pRb, hypophosphorylated; ppRb, hyperphosphorylated Rb.

We also investigated a second cell cycle-regulated protein, p27kip1. The addition of IL-2 to resting CT6 cells induces the degradation of p27kip1(Fig. 2c). This degradation was unaffected by SB203580, which if anything, further reduced levels of the protein. Wortmannin and LY294002 similarly had no inhibitory effect on p27kip1 degradation. Again, these studies on p27kip1 degradation were repeated in activated primary human T cells, with no significant inhibition observed with SB203580 or wortmannin, although LY294002 had some inhibitory effect (Fig. 2e).

SB203580 Inhibits the Phosphorylation and Activation of PKB-- The characteristic, S-phase hyperphosphorylation of Rb induced by IL-2 has been reported to be mediated by the PI 3-kinase pathway via the distal effector PKB (10). Furthermore, both the mitogenic and survival functions of the PI 3-kinase pathway have, in several reports, been attributed to PKB (10, 15, 19-22). We were therefore interested in investigating the possibility that SB203580 mediates its effects on Rb by inhibiting these kinases, especially as wortmannin and LY294002 displayed similar effects. The activation of PKB requires the PI 3-kinase-generated second messenger PIP3 as well as phosphorylation on Thr308 and Ser473 mediated by the PIP3-dependent kinases, PDK1 and PDK2, respectively (23, 24). We investigated the effect of SB203580 on PKB activation by looking at IL-2-induced phosphorylation of residue Ser473 of PKB in whole cell lysates using a phospho-specific antibody. In both CT6 and activated human T cells, SB203580 inhibited the phosphorylation of Ser473 in a dose-dependent manner (Fig. 3, a and b). Similar studies on the IL-2-responsive BA/F3 F7 B cells gave the same result (Fig. 3c). The approximate IC50 for the effect of SB203580 on this parameter is ~5 µM, similar to the concentration required for the inhibitory effects on proliferation (Fig. 1). As expected, wortmannin (Fig. 3) and LY294002 (not shown) also inhibited Ser473 phosphorylation, whereas rapamycin (not shown) had no effect. The phosphorylation of PKB on Thr308 was similarly investigated. As the antibody was not so effective, PKB was first immunoprecipitated, and phospho-Thr308 was detected by Western blotting. SB203580 inhibited Thr308 phosphorylation in CT6 cells with similar efficacy to the Ser473 phosphorylation (Fig. 4). Wortmannin, as expected, also inhibited this Thr308 phosphorylation. To confirm that the effects of SB203580 on PKB phosphorylation correlated with kinase activity, assays were performed on immunoprecipitated PKB from IL-2-stimulated CT6 cells (Fig. 5). The drug inhibited PKB activation with an IC50 of 3-10 µM, in agreement with its effects on phosphorylation of the kinase and cell proliferation.


View larger version (47K):
[in this window]
[in a new window]
 
Fig. 3.   Effect of SB203580 on serine 473 phosphorylation of PKB. CT6 cells (a), activated human T cells (b), and BA/F3 F7 cells (c) were preincubated with 0-30 µM SB203580 or vehicle control for 1 h or 100 nM wortmannin for 15 min before stimulating with 20 ng/ml IL-2 or vehicle control for 5 min. PKB phosphoserine 473 (upper panels) was detected by Western blotting. Membranes were stripped and reprobed for total PKB to confirm equal loading (lower panels). The data are representative of three separate experiments.


View larger version (15K):
[in this window]
[in a new window]
 
Fig. 4.   Effect of SB203580 on phosphorylation of threonine-308 on PKB. Rested CT6 were preincubated with the indicated doses of SB203580 or vehicle control for 1 h or 100 nM wortmannin for 15 min before stimulating with 20 ng/ml IL-2 or vehicle control for 5 min. Cells were then lysed, and PKB was immunoprecipitated (IP) with anti-PKBalpha antiserum or irrelevant control antibody. Threonine 308 phosphorylation was assayed by Western blotting (upper panel). Membranes were stripped and reprobed for total PKB to confirm equal loading (lower panel).


View larger version (29K):
[in this window]
[in a new window]
 
Fig. 5.   SB203580 inhibits IL-2-induced PKB activity. Rested CT6 cells per sample were preincubated with indicated concentrations of SB203580, wortmannin, or vehicle control before stimulating with 20 ng/ml IL-2 or vehicle control for 5 min. Immunokinase assays were performed as described under "Experimental Procedures." Panel a is representative of three separate experiments. b, the accumulated data from the three experiments is represented graphically showing inhibition of PKB activity as a percentage of uninhibited, IL-2-activated controls. Error bars equal ± S.D. (n = 3).

SB203580 Inhibits the Activation of p70S6 Kinase but Not PI 3-Kinase-- Although the above results showed that PKB activation is inhibited, it is still possible that PKB is one of several mitogenic effector molecules downstream of the actual SB203580 target. Therefore the effect of SB203580 on IL-2-induced activation of the PI 3-kinase/PKB pathway was examined. Exposure of CT6 cells to IL-2 leads to a reproducible 2-fold increase in anti-p85-precipitable PI 3-kinase activity. This was unaffected by preincubating the cells with SB203580. In contrast, wortmannin totally inhibited this activity (Fig. 6). Furthermore, direct addition of SB203580 to PI 3-kinase assays did not have any effect (results not shown), indicating that PI 3-kinase is not the target of the drug. The effect of SB203580 on PI 3-kinase/PKB pathway was also examined indirectly. Several studies have shown that p70S6 kinase is a distal mediator of PI 3-kinase activity in several systems (15, 25). As expected, wortmannin (Fig. 6b) and LY294002 (not shown) inhibited the activation of p70S6 kinase by IL-2, as measured in immunokinase assays. We observed that SB203580 could also inhibit IL-2-induced p70S6 kinase activation, although the concentration required was slightly higher with an IC50 above 10 µM. These observations place the target of SB203580 downstream of PI 3-kinase but upstream of p70S6 kinase. Furthermore, it suggests that the SB203580 target is a common activator of both PKB and p70S6 kinase. The most likely candidate is PDK1, which has been reported to phosphorylate and activate p70S6 kinase. The higher IC50 for p70S6 kinase activation may reflect the fact that PDK1 contributes to only one of several phosphorylations required for p70S6 kinase activation.


View larger version (41K):
[in this window]
[in a new window]
 
Fig. 6.   Effect of SB203580 on the activation of PI 3-kinase and p70S6 kinase. Rested cells were preincubated with indicated concentrations of SB203580, wortmannin, or vehicle control before stimulating with 20 ng/ml IL-2 or vehicle control for 5 min. Representative immunokinase assays for PI 3-kinase showing fold activation over unstimulated cells (a) and p70S6 kinase with % inhibition of IL-2-stimulated activity labeled on top of peptide gel panel (b) are shown. The PI 3-kinase experiment is representative of two, and the p70S6 kinase experiment is representative of three repeat experiments.

SB203580 Can Act as an Inhibitor of PDK1-- The data so far suggest that PDK1 and/or PDK2, the PKB kinases, are possible targets for SB203580. The Thr308 kinase, PDK1, is a constitutively active enzyme (26), but the phosphorylation of PKB on Thr308 is regulated by PIP3. The kinase for Ser473, a putative PDK2, is so named because it is also dependent on PIP3, but PDK2 has not been fully characterized, and as a result, no direct assays are available to examine its activity. Because we had evidence that PI 3-kinase activity and, therefore, PIP3 production are not inhibited (Fig. 6a), we examined whether SB203580 could act as a PDK1 inhibitor. To do this, recombinant kinase was used with recombinant PKB as the substrate. Activity of the enzyme was assessed by measuring the incorporation of [32P]phosphate into PKB (Fig. 7a). SB203580 was able to inhibit the activity of PDK1 in a dose-dependent manner with an IC50 in the 3-10 µM range, but CNI-1493, an inhibitor of p38MAP kinase activation (6), did not affect PDK1 activity. The recombinant PKB used in this assay, but not the PDK1, had endogenous autokinase activity (results not shown), so we tested the effect of the drug on this (Fig. 7b). SB203580 was unable to inhibit PKB autokinase activity. The inhibition of PDK1 by SB203580 identifies it as the putative target in the PI 3-kinase pathway, in agreement with its reported role in p70S6 kinase activation (27, 28) and supported by our finding above (Fig. 6b).


View larger version (29K):
[in this window]
[in a new window]
 
Fig. 7.   SB 203580 inhibits PDK1 activity. Recombinant PDK1 activity was assayed after preincubation with 0-30 µM SB203580 or 5 µM CNI-1493 using recombinant PKB as substrate (a). PKB autokinase activity was measured using recombinant PKB in the absence of PDK-1 or PIP3 (b). Reactions were performed as described under "Experimental Procedures." Data is expressed as the percentage of total activity obtained with a 5-min incubation in the absence of inhibitor. The figures are each representative of three separate experiments.

p38 MAP Kinase Is Not Involved in PKB Phosphorylation-- Although the above data demonstrate that SB203580 is an inhibitor of the PKB kinases (PDK1 and by inference PDK2), it was important to discriminate between the effects of SB203580 on PKB activation and the p38 MAP kinase pathway. The compound, CNI-1493 can inhibit the phosphorylation and activation of p38 MAP kinase induced by IL-2 and lipopolysaccharide (5-7). Therefore the effect of CNI-1493 on the IL-2-induced phosphorylation of p38 MAP kinase was compared with that of PKB. This study was performed in BA/F3 F7 cells because the IL-2-induced phosphorylation of p38 MAP kinase was easier to detect in these cells compared with T cells.2 CNI-1493 inhibited IL-2-induced phosphorylation of p38 MAP kinase in the dose range 0.5 to 5 µM while having no effect on PKB phosphorylation at Ser473 (Fig. 8). In contrast, wortmannin inhibited PKB phosphorylation and was consistently found to enhance the IL-2-induced phosphorylation of p38 MAP kinase (data not shown), an observation supported by kinase assays (not shown). These data would discount any role for p38 MAP kinase in the regulation of PKB either distal or proximal of PI 3-kinase. The data would also indicate that IL-2-induced PKB and p38 MAP kinase are likely to be on separate IL-2-mediated signaling pathways.


View larger version (9K):
[in this window]
[in a new window]
 
Fig. 8.   p38 MAP kinase is not required for PKB phosphorylation. BA/F3 F7 cells were stimulated with 20 ng/ml IL-2 for 15 min following preincubation with 0-5 µM CNI-1493 or vehicle control. Cell extracts were then separated by SDS-polyacrylamide gel electrophoresis and transferred onto polyvinylidene difluoride. The membrane was cut in half and immunoblotted for the phosphorylation of p38 MAP kinase (upper panel) and PKB (lower panel). The upper panel was reprobed for p38 MAP kinase (not shown) and showed equal loading on all tracks.


    DISCUSSION
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

Since the original description of the pyridinyl imidazole SB203580 as a specific inhibitor of p38 MAP kinase, the drug has been widely used as a research tool. The correlation drawn between the effects of SB203580 and a role for p38 MAP kinase has been applied to many systems with several hundred publications to date. Although the IC50 for inhibition of p38 MAP kinase activity has been shown to be approximately 0.3 µM (4, 29), many studies have used SB203580 at higher concentrations, often at 10-30 µM or even up to 100 µM (30, 31). Recently two studies have shown that SB203580 could inhibit certain subtypes of the related p54 MAP kinase (JNK/SAPK1) at concentrations of 5-10 µM (8, 9). This is an added complication in the interpretation of results obtained with SB203580, as p54 MAP kinase is often activated in tandem with p38 MAP kinase. However, our recently published findings (5) indicate that the inhibitory effect of SB203580 on proliferation driven by IL-2 was not related to either p38 or p54 MAP kinase function and that the drug was likely to have some other target.

We found that SB203580 in excess of 3 µM had effects on IL-2-induced hyperphosphorylation of Rb that were similar to those of the PI 3-kinase inhibitors, wortmannin and LY294002. This led us to investigate the effects of the inhibitor on the PI 3-kinase/PDK1/PKB pathway. Our data show that SB203580 inhibits the activation of PKB by blocking the phosphorylation of the kinase on the residues Thr308 and Ser473, that are required for kinase function. Furthermore, we have shown that SB203580 inhibits PDK1, the Thr308 kinase, in vitro. The inhibition of Ser473 phosphorylation by the drug is in agreement with the recent publication by Balendran et al. (11) that PDK1 also acts as PDK2 once bound to protein kinase C-related protein kinase-2 (PRK2). The IC50 of SB203580 for the inhibition of PKB phosphorylation is commensurate with that for the antiproliferative effects of the drug. The putative role of PKB in mediating proliferation induced by IL-2 (10) could provide a mechanism for this effect of SB203580. The compound also inhibited the phosphorylation of PKB induced by IL-43 or the antibody-induced cross-linking of CD45,4 showing that the effect of SB203580 is not confined to IL-2 signaling. However, our data disagree with the recent study of Sweeney et al. (32), which shows no inhibition of insulin-induced PKB activation in adipocytes by SB203580. A recent study by Shaw et al. also reports no inhibition of PKB activation in response to cellular stress in SW 3T3 and 293 cells (33). Although both studies used 10 µM SB203580, a concentration at which we see up to 50% inhibition of IL-2-induced PKB activity, they were performed on different lineages of cells from those used in our studies, and furthermore, the stress-activated PKB responses display much slower kinetics compared with the mitogen-induced activation in our studies. It is possible that the cell type or stimulus may modulate the effects of SB203580 on PKB activation. In our studies, the drug inhibited IL-2 responses in both T and B cells.

Following our observations that, at higher concentrations, SB203580 inhibited PKB activation, it was important to distinguish between the effects of the drug on the p38 MAP kinase and PKB pathways. Alessi et al. (34) show that the p38 MAP kinase substrate, MAPKAP kinase-2, could also act as a Ser473 kinase. However, this effect could only be shown with the purified proteins, and the study found no evidence that this occurred in intact cells. Furthermore, a recent study by the same group reported that insulin-like growth factor-1 activated PKB in the absence of p38 MAP kinase activation (33). These studies support our own finding that the compound CNI-1493, which blocks p38 MAP kinase activation by IL-2 (5), had no effect on PKB phosphorylation. In agreement with these observations, we have previously shown that inhibition of IL-2-induced MAPKAP kinase-2 activation by SB203580 had an IC50 of 0.3 µM (4), which is 10-20-fold lower that that required to inhibit PKB phosphorylation. Also, the kinetics of p38 MAP kinase activation is not consistent with a role in IL-2-induced PKB activation. Phosphorylation of PKB is maximal at 5 min, whereas activation of p38 MAP kinase takes 15 min (4). Finally, the study of Alessi et al. (34) shows that MAPKAP kinase-2 did not act as a Thr308 kinase.

Although our data discount a role for p38 MAP kinase in PKB activation, a recent work by Wang et al. (35) reports that Fas-mediated hyperphosphorylation of Rb is p38 MAP kinase-dependent. Because the concentrations of SB203580 used in our study totally inhibit the p38 MAP kinase signaling, the observations of Wang et al. could provide an explanation for the changes we see in Rb phosphorylation. However the reduction we see in Rb phosphorylation does not occur at the lower concentrations of SB203580, which totally inhibit p38 MAP kinase activity in our cells (IC50 = 0.3-0.5 µM (4)). The need to use higher concentrations of SB203580 dissociates the mitogen-induced hyperphosphorylation of Rb from the p38 MAP kinase pathway in our system. Furthermore, it would be interesting to see if an inhibitor of p38 MAP kinase activation, CNI-1493 has a similar effect on Fas-induced Rb hyperphosphorylation.

The effect of SB203580 on the PI 3-kinase-mediated activation of PKB supports the reported role for these kinases in cellular proliferation and survival. In particular, the identification of PDK1 as a putative target of SB203580 provides a possible mechanism for this effect. However in the context of IL-2 signaling, the effect of SB203580 appears to be solely on cell cycle progression, as we have found no evidence of increased apoptosis in treated cells. It would be interesting to see if the phosphorylation of Bad, which can be mediated by PKB (36, 37), is affected by SB203580. The inhibitory effect of SB203580 on the activation of p70S6 kinase in vivo would agree with recent studies that have identified this kinase as a substrate for PDK1 (26, 28). Additionally, PKB has been reported to play a role in p70S6 kinase activation. Although data from membrane-targeted PKB support this putative role in p70S6 kinase activation (38), Dufner et al. (39) find this activity only in the membrane-targeted form of PKB and argue that it may not reflect the normal mechanism of p70S6 kinase activation. The observations made in our study, however, remain consistent with a model of PI 3-kinase signaling in which PDK1 is upstream of both 70S6 kinase and PKB. Besides the established downstream effectors of PI 3-kinase-signaling discussed above, the pathway has also been implicated in the regulation of cell cycle proteins (10). Our findings on Rb regulation agree with these observations. The lack of effect of SB203580 (or wortmannin and LY294002) on p27kip1 degradation, however, was surprising, since previous work on Kit-225 T cells suggested a role for PKB in IL-2-induced p27kip1 degradation (10).

These observations raise questions concerning studies that have used the inhibitory effects of SB203580 as a confirmation of the involvement of p38 MAP kinase in a given cellular activity. Although previous reports (29, 40) and our own work (4) would suggest that at concentrations of <1 µM the effects of SB203580 can still be correlated with inhibition of p38 MAP kinase activity, we now submit that at higher concentrations, extreme caution must be exercised in interpreting data. Our observations do not establish a requirement for PDK1 or PKB activity in Rb phosphorylation but suggest a role for these kinases and their distal effectors in Rb regulation. Furthermore, the data do not preclude a role for novel targets of SB203580 in mediating Rb phosphorylation and T cell proliferation.

In summary, we have putatively identified PDK1/PDK2 as targets for the pyridinyl imidazole p38 MAP kinase inhibitor SB203580, which could, at least in part, explain the antiproliferative effect of the drug. The observation that SB203580 can inhibit PI 3-kinase/PDK1/PKB pathway could have major implications for the interpretation of data obtained with this drug.

    ACKNOWLEDGEMENTS

We thank Professors Feldmann, Saklatvala, and Cantrell and Drs. Davies, Dean, and Finch for reading the manuscript and S. Johns for typing the manuscript. We also thank Professor Taniguchi, Dr. K. Tracey, and Drs. Alessi and Stephens for their gifts of reagents.

    FOOTNOTES

* The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

Dagger Supported by grants from the BBSRC (UK), Rhone Poulenc-Rorer, The Arthritis and Rheumatism Campaign (UK), and the Wellcome Trust.

§ To whom all correspondence should be addressed: Kennedy Instititute of Rheumatology, 1 Aspenlea Rd., London W6 8LH, UK. Tel.: 44-208 383 4444; E-mail: b.foxwell@cxwms.ac.uk.

2 F. V. Lali, A. E. Hunt, S. J. Turner, and B. M. J. Foxwell, unpublished observations.

3 A. Hunt and B. M. J. Foxwell, unpublished observations.

4 L. Hayes, unpublished observations.

    ABBREVIATIONS

The abbreviations used are: IL, interleukin; MAP, mitogen-activated protein; PKB, protein kinase B; PDK, 3-phosphoinositide-dependent protein kinase; Rb, retinoblastoma; PI, phosphatidylinositol; JNK, c-Jun NH2-terminal kinase; SAPK, stress-activated protein kinase; MOPS, 4-morpholinepropanesulfonic acid; DTT, dithiothreitol; PIP3, phosphatidylinositol 3,4,5-trisphosphate.

    REFERENCES
TOP
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
REFERENCES

1. Crawley, J. B., Willcocks, J., and Foxwell, B. M. (1996) Eur. J. Immunol. 26, 2717-2723[Medline] [Order article via Infotrieve]
2. Minami, Y., Oishi, I., Liu, Z. J., Nakagawa, S., Miyazaki, T., and Taniguchi, T. (1994) J. Immunol. 152, 5680-5690[Abstract]
3. Evans, G. A., Goldsmith, M. A., Johnston, J. A., Xu, W., Weiler, S. R., Erwin, R., Howard, O. M. Z., Abraham, R. T., O'Shea, J. J., Greene, W. C., and Farrar, W. L. (1995) J. Biol. Chem. 270, 28858-28863[Abstract/Free Full Text]
4. Crawley, J. B., Rawlinson, L., Lali, F. V., Page, T. H., Saklatvala, J., and Foxwell, B. M. J. (1997) J. Biol. Chem. 272, 15023-15027[Abstract/Free Full Text]
5. Hunt, A. E., Lali, F. V., Lord, J. D., Nelson, B. H., Miyazaki, T., Tracey, K. J., and Foxwell, B. M. J. (1999) J. Biol. Chem. 274, 7591-7597[Abstract/Free Full Text]
6. Bianchi, M., Bloom, O., Raabe, T., Cohen, P. S., Chesney, J., Sherry, B., Schmidtmayerova, H., Calandra, T., Zhang, X., Bukrinsky, M., Ulrich, P., Cerami, A., and Tracey, K. J. (1996) J. Exp. Med. 183, 927-936[Abstract/Free Full Text]
7. Cohen, P. S., Nakshatri, H., Dennis, J., Caragine, T., Bianchi, M., Cerami, A., and Tracey, K. J. (1996) Proc. Natl. Acad. Sci. U. S. A. 93, 3967-3971[Abstract/Free Full Text]
8. Whitmarsh, A. J., Yang, S. H., Su, M. S., Sharrocks, A. D., and Davis, R. J. (1997) Mol. Cell. Biol. 17, 2360-2371[Abstract]
9. Clerk, A., and Sugden, P. H. (1998) FEBS Lett. 426, 93-96[CrossRef][Medline] [Order article via Infotrieve]
10. Brennan, P., Babbage, J. W., Burgering, B. M., Groner, B., Reif, K., and Cantrell, D. A. (1997) Immunity 7, 679-689[CrossRef][Medline] [Order article via Infotrieve]
11. Balendran, A., Casamayor, A., Deak, M., Paterson, A., Gaffney, P., Currie, R., Downes, C. P., and Alessi, D. R. (1999) Curr. Biol. 9, 393-404[CrossRef][Medline] [Order article via Infotrieve]
12. Willcocks, J. L., Hales, A., Page, T. H., and Foxwell, B. M. (1993) Eur. J. Immunol. 23, 716-720[Medline] [Order article via Infotrieve]
13. Hatakeyama, M., Mori, H., Doi, T., and Taniguchi, T. (1989) Cell 59, 837-845[CrossRef][Medline] [Order article via Infotrieve]
14. Page, T. H., Lali, F. V., Groome, N., and Foxwell, B. M. (1997) J. Immunol. 158, 5727-5735[Abstract]
15. Crawley, J. B., Williams, L. M., Mander, T., Brennan, F. M., and Foxwell, B. M. J. (1996) J. Biol. Chem. 271, 16357-16362[Abstract/Free Full Text]
16. Janicke, R. U., Walker, P. A., Lin, X. Y., and Porter, A. G. (1996) EMBO J. 15, 6969-6978[Medline] [Order article via Infotrieve]
17. Dou, Q. P., An, B., Antoku, K., and Johnson, D. E. (1997) J. Cell. Biochem. 64, 586-594[CrossRef][Medline] [Order article via Infotrieve]
18. Gottlieb, E., and Oren, M. (1998) EmBO J. 17, 3587-3596[CrossRef][Medline] [Order article via Infotrieve]
19. Bacqueville, D., Casagrande, F., Perret, B., Chap, H., Darbon, J. M., and Breton-Douillon, M. (1998) Biochem. Biophys. Res. Commun. 244, 630-636[CrossRef][Medline] [Order article via Infotrieve]
20. Belham, C. M., Scott, P. H., Twomey, D. P., Gould, G. W., Wadsworth, R. M., and Plevin, R. (1997) Cell. Signal. 9, 109-116[CrossRef][Medline] [Order article via Infotrieve]
21. Ahmed, N. N., Grimes, H. L., Bellacosa, A., Chan, T. O., and Tsichlis, P. N. (1997) Proc. Natl. Acad. Sci. U. S. A. 94, 3627-3632[Abstract/Free Full Text]
22. Haas-Kogan, D., Shalev, N., Wong, M., Mills, G., Yount, G., and Stokoe, D. (1998) Curr. Biol. 8, 1195-1198[CrossRef][Medline] [Order article via Infotrieve]
23. Alessi, D. R., James, S. R., Downes, C. P., Holmes, A. B., Gaffney, P. R., Reese, C. B., and Cohen, P. (1997) Curr. Biol. 7, 261-269[CrossRef][Medline] [Order article via Infotrieve]
24. Anderson, K. E., Coadwell, J., Stephens, L. R., and Hawkins, P. T. (1998) Curr. Biol. 8, 684-691[CrossRef][Medline] [Order article via Infotrieve]
25. Calvo, V., Crews, C. M., Vik, T. A., and Bierer, B. E. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 7571-7575[Abstract/Free Full Text]
26. Pullen, N., Dennis, P. B., Andjelkovic, M., Dufner, A., Kozma, S. C., Hemmings, B. A., and Thomas, G. (1998) Science 279, 707-710[Abstract/Free Full Text]
27. Dennis, P. B., Pullen, N., Pearson, R. B., Kozma, S. C., and Thomas, G. (1998) J. Biol. Chem. 273, 14845-14852[Abstract/Free Full Text]
28. Alessi, D. R., Kozlowski, M. T., Weng, Q. P., Morrice, N., and Avruch, J. (1998) Curr. Biol. 8, 69-81[CrossRef][Medline] [Order article via Infotrieve]
29. Cuenda, A., Rouse, J., Doza, Y. N., Meier, R., Cohen, P., Gallagher, T. F., Young, P. R., and Lee, J. C. (1995) FEBS Lett. 364, 229-233[CrossRef][Medline] [Order article via Infotrieve]
30. Zhang, J., Salojin, K. V., Gao, J. X., Cameron, M. J., Bergerot, I., and Delovitch, T. L. (1999) J. Immunol. 162, 3819-3829[Abstract/Free Full Text]
31. Ozaki, I., Tani, E., Ikemoto, H., Kitagawa, H., and Fujikawa, H. (1999) J. Biol. Chem. 274, 5310-5317[Abstract/Free Full Text]
32. Sweeney, G., Somwar, R., Ramlal, T., Volchuk, A., Ueyama, A., and Klip, A. (1999) J. Biol. Chem. 274, 10071-10078[Abstract/Free Full Text]
33. Shaw, M., Cohen, P., and Alessi, D. R. (1998) Biochem. J. 336, 241-246
34. Alessi, D. R., Andjelkovic, M., Caudwell, B., Cron, P., Morrice, N., Cohen, P., and Hemmings, B. A. (1996) EMBO J. 15, 6541-6551[Medline] [Order article via Infotrieve]
35. Wang, S., Nath, N., Minden, A., and Chellappan, S. (1999) EMBO J. 18, 1559-1570[CrossRef][Medline] [Order article via Infotrieve]
36. del Peso, L., Gonzalez-Garcia, M., Page, C., Herrera, R., and Nunez, G. (1997) Science 278, 687-689[Abstract/Free Full Text]
37. Datta, S. R., Dudek, H., Tao, X., Masters, S., Fu, H., Gotoh, Y., and Greenberg, M. E. (1997) Cell 91, 231-241[CrossRef][Medline] [Order article via Infotrieve]
38. Reif, K., Burgering, B. M. T., and Cantrell, D. A. (1997) J. Biol. Chem. 272, 14426-14433[Abstract/Free Full Text]
39. Dufner, A., Andjelkovic, M., Burgering, B. M. T., Hemmings, B. A., and Thomas, G. (1999) Mol. Cell. Biol. 19, 4525-4534[Abstract/Free Full Text]
40. Lee, J. C., Laydon, J. T., McDonnell, P. C., Gallagher, T. F., Kumar, S., Green, D., McNulty, D., Blumenthal, M. J., Heys, J. R., Landvatter, S. W., Strickler, J. E., McLaughlin, M. M., Siemens, I. R., Fisher, S. M., Livi, G. P., White, J. R., Adams, J. L., and Young, P. R. (1994) Nature 372, 739-746[CrossRef][Medline] [Order article via Infotrieve]


Copyright © 2000 by The American Society for Biochemistry and Molecular Biology, Inc.
Add to CiteULike CiteULike   Add to Complore Complore   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us   Add to Digg Digg   Add to Reddit Reddit   Add to Technorati Technorati    What's this?


This article has been cited by other articles:


Home page
J EndocrinolHome page
K. Ishizawa, N. Dorjsuren, Y. Izawa-Ishizawa, R. Sugimoto, Y. Ikeda, Y. Kihira, K. Kawazoe, S. Tomita, K. Tsuchiya, K. Minakuchi, et al.
Inhibitory effects of adiponectin on platelet-derived growth factor-induced mesangial cell migration
J. Endocrinol., August 1, 2009; 202(2): 309 - 316.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
Q. Zhao, B. M. Barakat, S. Qin, A. Ray, M. A. El-Mahdy, G. Wani, E.-S. Arafa, S. N. Mir, Q.-E. Wang, and A. A. Wani
The p38 Mitogen-activated Protein Kinase Augments Nucleotide Excision Repair by Mediating DDB2 Degradation and Chromatin Relaxation
J. Biol. Chem., November 21, 2008; 283(47): 32553 - 32561.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
H. Kawamura, X. Li, K. Goishi, L. A. van Meeteren, L. Jakobsson, S. Cebe-Suarez, A. Shimizu, D. Edholm, K. Ballmer-Hofer, L. Kjellen, et al.
Neuropilin-1 in regulation of VEGF-induced activation of p38MAPK and endothelial cell organization
Blood, November 1, 2008; 112(9): 3638 - 3649.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
V. Sorensen, Y. Zhen, M. Zakrzewska, E. M. Haugsten, S. Walchli, T. Nilsen, S. Olsnes, and A. Wiedlocha
Phosphorylation of Fibroblast Growth Factor (FGF) Receptor 1 at Ser777 by p38 Mitogen-Activated Protein Kinase Regulates Translocation of Exogenous FGF1 to the Cytosol and Nucleus
Mol. Cell. Biol., June 15, 2008; 28(12): 4129 - 4141.
[Abstract] [Full Text] [PDF]


Home page
Mol. Biol. CellHome page
H. Wang, Q. Xu, F. Xiao, Y. Jiang, and Z. Wu
Involvement of the p38 Mitogen-activated Protein Kinase {alpha}, {beta}, and {gamma} Isoforms in Myogenic Differentiation
Mol. Biol. Cell, April 1, 2008; 19(4): 1519 - 1528.
[Abstract] [Full Text] [PDF]


Home page
J. Neurosci.Home page
N. Origlia, M. Righi, S. Capsoni, A. Cattaneo, F. Fang, D. M. Stern, J. X. Chen, A. M. Schmidt, O. Arancio, S. D. Yan, et al.
Receptor for Advanced Glycation End Product-Dependent Activation of p38 Mitogen-Activated Protein Kinase Contributes to Amyloid-{beta}-Mediated Cortical Synaptic Dysfunction
J. Neurosci., March 26, 2008; 28(13): 3521 - 3530.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
N. Henderson, L. J. Markwick, S. R. Elshaw, A. M. Freyer, A. J. Knox, and S. R. Johnson
Collagen I and thrombin activate MMP-2 by MMP-14-dependent and -independent pathways: implications for airway smooth muscle migration
Am J Physiol Lung Cell Mol Physiol, April 1, 2007; 292(4): L1030 - L1038.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Respir. Cell Mol. Bio.Home page
I. H. Heijink, P. Marcel Kies, A. J. M. van Oosterhout, D. S. Postma, H. F. Kauffman, and E. Vellenga
Der p, IL-4, and TGF-beta Cooperatively Induce EGFR-Dependent TARC Expression in Airway Epithelium
Am. J. Respir. Cell Mol. Biol., March 1, 2007; 36(3): 351 - 359.
[Abstract] [Full Text] [PDF]


Home page
Biol. Reprod.Home page
C. LaRosa and S. M. Downs
Meiotic Induction by Heat Stress in Mouse Oocytes: Involvement of AMP-Activated Protein Kinase and MAPK Family Members
Biol Reprod, March 1, 2007; 76(3): 476 - 486.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Respir. Cell Mol. Bio.Home page
Y. Wang, M. M. Zeigler, G. K. Lam, M. G. Hunter, T. D. Eubank, V. V. Khramtsov, S. Tridandapani, C. K. Sen, and C. B. Marsh
The Role of the NADPH Oxidase Complex, p38 MAPK, and Akt in Regulating Human Monocyte/Macrophage Survival
Am. J. Respir. Cell Mol. Biol., January 1, 2007; 36(1): 68 - 77.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
Y. Osawa, S. Iho, R. Takauji, H. Takatsuka, S. Yamamoto, T. Takahashi, S. Horiguchi, Y. Urasaki, T. Matsuki, and S. Fujieda
Collaborative Action of NF-{kappa}B and p38 MAPK Is Involved in CpG DNA-Induced IFN-{alpha} and Chemokine Production in Human Plasmacytoid Dendritic Cells
J. Immunol., October 1, 2006; 177(7): 4841 - 4852.
[Abstract] [Full Text] [PDF]


Home page
J Mol EndocrinolHome page
Y. S. Kang, Y. G. Park, B. K. Kim, S. Y. Han, Y. H. Jee, K. H. Han, M. H. Lee, H. K. Song, D. R. Cha, S. W. Kang, et al.
Angiotensin II stimulates the synthesis of vascular endothelial growth factor through the p38 mitogen activated protein kinase pathway in cultured mouse podocytes.
J. Mol. Endocrinol., April 1, 2006; 36(2): 377 - 388.
[Abstract] [Full Text] [PDF]


Home page
J. Pharmacol. Exp. Ther.Home page
M. A. Birrell, S. Wong, K. McCluskie, M. C. Catley, E. L. Hardaker, S. Haj-Yahia, and M. G. Belvisi
Second-Generation Inhibitors Demonstrate the Involvement of p38 Mitogen-Activated Protein Kinase in Post-Transcriptional Modulation of Inflammatory Mediator Production in Human and Rodent Airways
J. Pharmacol. Exp. Ther., March 1, 2006; 316(3): 1318 - 1327.
[Abstract] [Full Text] [PDF]


Home page
Eur J EndocrinolHome page
C Correze, J-P Blondeau, and M Pomerance
p38 mitogen-activated protein kinase contributes to cell cycle regulation by cAMP in FRTL-5 thyroid cells
Eur. J. Endocrinol., July 1, 2005; 153(1): 123 - 133.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
G. Lominadze, M. J. Rane, M. Merchant, J. Cai, R. A. Ward, and K. R. McLeish
Myeloid-Related Protein-14 Is a p38 MAPK Substrate in Human Neutrophils
J. Immunol., June 1, 2005; 174(11): 7257 - 7267.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Cell Physiol.Home page
H. Shiratsuchi and M. D. Basson
Activation of p38 MAPK{alpha} by extracellular pressure mediates the stimulation of macrophage phagocytosis by pressure
Am J Physiol Cell Physiol, May 1, 2005; 288(5): C1083 - C1093.
[Abstract] [Full Text] [PDF]


Home page
J. Pharmacol. Exp. Ther.Home page
Y.-L. Hsu, P.-L. Kuo, L.-T. Lin, and C.-C. Lin
Asiatic Acid, a Triterpene, Induces Apoptosis and Cell Cycle Arrest through Activation of Extracellular Signal-Regulated Kinase and p38 Mitogen-Activated Protein Kinase Pathways in Human Breast Cancer Cells
J. Pharmacol. Exp. Ther., April 1, 2005; 313(1): 333 - 344.
[Abstract] [Full Text] [PDF]


Home page
Mol. Pharmacol.Home page
S. Rakhit, C. J. Clark, C. T. O'Shaughnessy, and B. J. Morris
N-Methyl-D-aspartate and Brain-Derived Neurotrophic Factor Induce Distinct Profiles of Extracellular Signal-Regulated Kinase, Mitogen- and Stress-Activated Kinase, and Ribosomal S6 Kinase Phosphorylation in Cortical Neurons
Mol. Pharmacol., April 1, 2005; 67(4): 1158 - 1165.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
A. Glasow, N. Prodromou, K. Xu, M. von Lindern, and A. Zelent
Retinoids and myelomonocytic growth factors cooperatively activate RARA and induce human myeloid leukemia cell differentiation via MAP kinase pathways
Blood, January 1, 2005; 105(1): 341 - 349.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
J. Campbell, C. J. Ciesielski, A. E. Hunt, N. J. Horwood, J. T. Beech, L. A. Hayes, A. Denys, M. Feldmann, F. M. Brennan, and B. M. J. Foxwell
A Novel Mechanism for TNF-{alpha} Regulation by p38 MAPK: Involvement of NF-{kappa}B with Implications for Therapy in Rheumatoid Arthritis
J. Immunol., December 1, 2004; 173(11): 6928 - 6937.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
H. Xiong, H. Li, Y. Chen, J. Zhao, and J. C. Unkeless
Interaction of TRAF6 with MAST205 Regulates NF-{kappa}B Activation and MAST205 Stability
J. Biol. Chem., October 15, 2004; 279(42): 43675 - 43683.
[Abstract] [Full Text] [PDF]


Home page
J. Leukoc. Biol.Home page
G. A. Ricchetti, L. M. Williams, and B. M. J. Foxwell
Heme oxygenase 1 expression induced by IL-10 requires STAT-3 and phosphoinositol-3 kinase and is inhibited by lipopolysaccharide
J. Leukoc. Biol., September 1, 2004; 76(3): 719 - 726.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. ProteomicsHome page
Z. Lin, D. K. Crockett, S. D. Jenson, M. S. Lim, and K. S. J. Elenitoba-Johnson
Quantitative Proteomic and Transcriptional Analysis of the Response to the p38 Mitogen-activated Protein Kinase Inhibitor SB203580 in Transformed Follicular Lymphoma Cells
Mol. Cell. Proteomics, August 1, 2004; 3(8): 820 - 833.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
I. Gonzalez, G. Tripathi, E. J. Carter, L. J. Cobb, D. A. M. Salih, F. A. Lovett, C. Holding, and J. M Pell
Akt2, a Novel Functional Link between p38 Mitogen-Activated Protein Kinase and Phosphatidylinositol 3-Kinase Pathways in Myogenesis
Mol. Cell. Biol., May 1, 2004; 24(9): 3607 - 3622.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
F. V. Lali, J. Crawley, D. A. McCulloch, and B. M. J. Foxwell
A Late, Prolonged Activation of the Phosphatidylinositol 3-Kinase Pathway Is Required for T Cell Proliferation
J. Immunol., March 15, 2004; 172(6): 3527 - 3534.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Regul. Integr. Comp. Physiol.Home page
R. C. Ho, O. Alcazar, N. Fujii, M. F. Hirshman, and L. J. Goodyear
p38{gamma} MAPK regulation of glucose transporter expression and glucose uptake in L6 myotubes and mouse skeletal muscle
Am J Physiol Regulatory Integrative Comp Physiol, February 1, 2004; 286(2): R342 - R349.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
J. J. Yu, C. S. Tripp, and J. H. Russell
Regulation and Phenotype of an Innate Th1 Cell: Role of Cytokines and the p38 Kinase Pathway
J. Immunol., December 1, 2003; 171(11): 6112 - 6118.
[Abstract] [Full Text] [PDF]


Home page
Mol. Cell. Biol.Home page
Y. Hirose, M. Katayama, D. Stokoe, D. A. Haas-Kogan, M. S. Berger, and R. O. Pieper
The p38 Mitogen-Activated Protein Kinase Pathway Links the DNA Mismatch Repair System to the G2 Checkpoint and to Resistance to Chemotherapeutic DNA-Methylating Agents
Mol. Cell. Biol., November 15, 2003; 23(22): 8306 - 8315.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
J. L. Smith, I. Collins, G. V. R. Chandramouli, W. G. Butscher, E. Zaitseva, W. J. Freebern, C. M. Haggerty, V. Doseeva, and K. Gardner
Targeting Combinatorial Transcriptional Complex Assembly at Specific Modules within the Interleukin-2 Promoter by the Immunosuppressant SB203580
J. Biol. Chem., October 17, 2003; 278(42): 41034 - 41046.
[Abstract] [Full Text] [PDF]


Home page
Drug Metab. Dispos.Home page
S. K. Kim, K. J. Woodcroft, S. G. Kim, and R. F. Novak
INSULIN AND GLUCAGON SIGNALING IN REGULATION OF MICROSOMAL EPOXIDE HYDROLASE EXPRESSION IN PRIMARY CULTURED RAT HEPATOCYTES
Drug Metab. Dispos., October 1, 2003; 31(10): 1260 - 1268.
[Abstract] [Full Text] [PDF]


Home page
EndocrinologyHome page
H.-J. Jeong, H.-J. Na, S.-H. Hong, and H.-M. Kim
Inhibition of the Stem Cell Factor-Induced Migration of Mast Cells by Dexamethasone
Endocrinology, September 1, 2003; 144(9): 4080 - 4086.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
S. M. Barry, D. G. Zisoulis, J. W. Neal, N. A. Clipstone, and G. S. Kansas
Induction of FucT-VII by the Ras/MAP kinase cascade in Jurkat T cells
Blood, September 1, 2003; 102(5): 1771 - 1778.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
M. Tanno, R. Bassi, D. A. Gorog, A. T. Saurin, J. Jiang, R. J. Heads, J. L. Martin, R. J. Davis, R. A. Flavell, and M. S. Marber
Diverse Mechanisms of Myocardial p38 Mitogen-Activated Protein Kinase Activation: Evidence for MKK-Independent Activation by a TAB1-Associated Mechanism Contributing to Injury During Myocardial Ischemia
Circ. Res., August 8, 2003; 93(3): 254 - 261.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
X. Guo, R. E. Gerl, and J. W. Schrader
Defining the Involvement of p38{alpha} MAPK in the Production of Anti- and Proinflammatory Cytokines Using an SB 203580-resistant Form of the Kinase
J. Biol. Chem., June 13, 2003; 278(25): 22237 - 22242.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Endocrinol. Metab.Home page
H. Tokuda, D. Hatakeyama, T. Shibata, S. Akamatsu, Y. Oiso, and O. Kozawa
p38 MAP kinase regulates BMP-4-stimulated VEGF synthesis via p70 S6 kinase in osteoblasts
Am J Physiol Endocrinol Metab, June 1, 2003; 284(6): E1202 - E1209.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Heart Circ. Physiol.Home page
J. Kaur, R. C. Woodman, and P. Kubes
P38 MAPK: critical molecule in thrombin-induced NF-kappa B-dependent leukocyte recruitment
Am J Physiol Heart Circ Physiol, April 1, 2003; 284(4): H1095 - H1103.
[Abstract] [Full Text] [PDF]


Home page
J. Cell Sci.Home page
S. Kiriakidis, E. Andreakos, C. Monaco, B. Foxwell, M. Feldmann, and E. Paleolog
VEGF expression in human macrophages is NF-{kappa}B-dependent: studies using adenoviruses expressing the endogenous NF-{kappa}B inhibitor I{kappa}B{alpha} and a kinase-defective form of the I{kappa}B kinase 2
J. Cell Sci., February 15, 2003; 116(4): 665 - 674.
[Abstract] [Full Text] [PDF]


Home page
J. Pharmacol. Exp. Ther.Home page
A. Masamune, M. Satoh, K. Kikuta, Y. Sakai, A. Satoh, and T. Shimosegawa
Inhibition of p38 Mitogen-Activated Protein Kinase Blocks Activation of Rat Pancreatic Stellate Cells
J. Pharmacol. Exp. Ther., January 1, 2003; 304(1): 8 - 14.
[Abstract] [Full Text] [PDF]


Home page
J. Am. Soc. Nephrol.Home page
R. Blaber, E. Stylianou, A. Clayton, and R. Steadman
Selective Regulation of ICAM-1 and RANTES Gene Expression after ICAM-1 Ligation on Human Renal Fibroblasts
J. Am. Soc. Nephrol., January 1, 2003; 14(1): 116 - 127.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
H. Sakamoto, T. Tosaki, and Y. Nakagawa
Overexpression of Phospholipid Hydroperoxide Glutathione Peroxidase Modulates Acetyl-CoA, 1-O-Alkyl-2-lyso-sn-glycero-3-phosphocholine Acetyltransferase Activity
J. Biol. Chem., December 20, 2002; 277(52): 50431 - 50438.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. Obrero, D. V. Yu, and D. J. Shapiro
Estrogen Receptor-dependent and Estrogen Receptor-independent Pathways for Tamoxifen and 4-Hydroxytamoxifen-induced Programmed Cell Death
J. Biol. Chem., November 15, 2002; 277(47): 45695 - 45703.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
I. Ringshausen, F. Schneller, C. Bogner, S. Hipp, J. Duyster, C. Peschel, and T. Decker
Constitutively activated phosphatidylinositol-3 kinase (PI-3K) is involved in the defect of apoptosis in B-CLL: association with protein kinase Cdelta
Blood, November 15, 2002; 100(10): 3741 - 3748.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. Zayzafoon, S. Botolin, and L. R. McCabe
p38 and Activating Transcription Factor-2 Involvement in Osteoblast Osmotic Response to Elevated Extracellular Glucose
J. Biol. Chem., September 27, 2002; 277(40): 37212 - 37218.
[Abstract] [Full Text] [PDF]


Home page
J. Cell Sci.Home page
A. Mauro, C. Ciccarelli, P. De Cesaris, A. Scoglio, M. Bouche, M. Molinaro, A. Aquino, and B. M. Zani
PKC{alpha}-mediated ERK, JNK and p38 activation regulates the myogenic program in human rhabdomyosarcoma cells
J. Cell Sci., September 15, 2002; 115(18): 3587 - 3599.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Gastrointest. Liver Physiol.Home page
C. R. L. Webster, P. Usechak, and M. S. Anwer
cAMP inhibits bile acid-induced apoptosis by blocking caspase activation and cytochrome c release
Am J Physiol Gastrointest Liver Physiol, September 1, 2002; 283(3): G727 - G738.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
D. Decraene, P. Agostinis, R. Bouillon, H. Degreef, and M. Garmyn
Insulin-like Growth Factor-1-mediated AKT Activation Postpones the Onset of Ultraviolet B-induced Apoptosis, Providing More Time for Cyclobutane Thymine Dimer Removal in Primary Human Keratinocytes
J. Biol. Chem., August 30, 2002; 277(36): 32587 - 32595.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
C. R. L. Webster, U. Srinivasulu, M. Ananthanarayanan, F. J. Suchy, and M. S. Anwer
Protein Kinase B/Akt Mediates cAMP- and Cell Swelling-stimulated Na+/Taurocholate Cotransport and Ntcp Translocation
J. Biol. Chem., August 2, 2002; 277(32): 28578 - 28583.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Respir. Cell Mol. Bio.Home page
H.-M. Wu, H.-C. Wen, and W.-W. Lin
Proteasome Inhibitors Stimulate Interleukin-8 Expression via Ras and Apoptosis Signal-Regulating Kinase-dependent Extracellular Signal-Related Kinase and c-Jun N-Terminal Kinase Activation
Am. J. Respir. Cell Mol. Biol., August 1, 2002; 27(2): 234 - 243.
[Abstract] [Full Text] [PDF]


Home page
Molecular Cancer TherapeuticsHome page
A. S. Clark, K. West, S. Streicher, and P. A. Dennis
Constitutive and Inducible Akt Activity Promotes Resistance to Chemotherapy, Trastuzumab, or Tamoxifen in Breast Cancer Cells
Mol. Cancer Ther., July 1, 2002; 1(9): 707 - 717.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
V. S. Carl, K. Brown-Steinke, M. J. H. Nicklin, and M. F. Smith Jr.
Toll-like Receptor 2 and 4 (TLR2 and TLR4) Agonists Differentially Regulate Secretory Interleukin-1 Receptor Antagonist Gene Expression in Macrophages
J. Biol. Chem., May 10, 2002; 277(20): 17448 - 17456.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
A. M. Gurnett, P. A. Liberator, P. M. Dulski, S. P. Salowe, R. G. K. Donald, J. W. Anderson, J. Wiltsie, C. A. Diaz, G. Harris, B. Chang, et al.
Purification and Molecular Characterization of cGMP-dependent Protein Kinase from Apicomplexan Parasites. A NOVEL CHEMOTHERAPEUTIC TARGET
J. Biol. Chem., May 3, 2002; 277(18): 15913 - 15922.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
L. J. Appleman, A. A. F. L. van Puijenbroek, K. M. Shu, L. M. Nadler, and V. A. Boussiotis
CD28 Costimulation Mediates Down-Regulation of p27kip1 and Cell Cycle Progression by Activation of the PI3K/PKB Signaling Pathway in Primary Human T Cells
J. Immunol., March 15, 2002; 168(6): 2729 - 2736.
[Abstract] [Full Text] [PDF]


Home page
Nucleic Acids ResHome page
A. Civil, S. T. van Genesen, and N. H. Lubsen
c-Maf, the {gamma}D-crystallin Maf-responsive element and growth factor regulation
Nucleic Acids Res., February 15, 2002; 30(4): 975 - 982.
[Abstract] [Full Text] [PDF]


Home page
BloodHome page
I. M. Pedersen, A. M. Buhl, P. Klausen, C. H. Geisler, and J. Jurlander
The chimeric anti-CD20 antibody rituximab induces apoptosis in B-cell chronic lymphocytic leukemia cells through a p38 mitogen activated protein-kinase-dependent mechanism
Blood, February 15, 2002; 99(4): 1314 - 1319.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
H. M. Tse, S. I. Josephy, E. D. Chan, D. Fouts, and A. M. Cooper
Activation of the Mitogen-Activated Protein Kinase Signaling Pathway Is Instrumental in Determining the Ability of Mycobacterium avium to Grow in Murine Macrophages
J. Immunol., January 15, 2002; 168(2): 825 - 833.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Lung Cell. Mol. Physiol.Home page
R. M. Pascual, C. K. Billington, I. P. Hall, R. A. Panettieri Jr., J. E. Fish, S. P. Peters, and R. B. Penn
Mechanisms of cytokine effects on G protein-coupled receptor-mediated signaling in airway smooth muscle
Am J Physiol Lung Cell Mol Physiol, December 1, 2001; 281(6): L1425 - L1435.
[Abstract] [Full Text] [PDF]


Home page
J. Leukoc. Biol.Home page
O. Werz, J. Klemm, O. Radmark, and B. Samuelsson
p38 MAP kinase mediates stress-induced leukotriene synthesis in a human B-lymphocyte cell line
J. Leukoc. Biol., November 1, 2001; 70(5): 830 - 838.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Cell Physiol.Home page
W. H. Loomis, S. Namiki, D. B. Hoyt, and W. G. Junger
Hypertonicity rescues T cells from suppression by trauma-induced anti-inflammatory mediators
Am J Physiol Cell Physiol, September 1, 2001; 281(3): C840 - C848.
[Abstract] [Full Text] [PDF]


Home page
Cancer Res.Home page
Y. Dai, C. Yu, V. Singh, L. Tang, Z. Wang, R. McInistry, P. Dent, and S. Grant
Pharmacological Inhibitors of the Mitogen-activated Protein Kinase (MAPK) Kinase/MAPK Cascade Interact Synergistically with UCN-01 to Induce Mitochondrial Dysfunction and Apoptosis in Human Leukemia Cells
Cancer Res., July 1, 2001; 61(13): 5106 - 5115.
[Abstract] [Full Text] [PDF]


Home page
J. Immunol.Home page
X. Zhu, H. Sano, K. P. Kim, A. Sano, E. Boetticher, N. M. Munoz, W. Cho, and A. R. Leff
Role of Mitogen-Activated Protein Kinase-Mediated Cytosolic Phospholipase A2 Activation in Arachidonic Acid Metabolism in Human Eosinophils
J. Immunol., July 1, 2001; 167(1): 461 - 468.
[Abstract] [Full Text] [PDF]


Home page
J. Am. Soc. Nephrol.Home page
M. FOSCHI, A. SOROKIN, P. PRATT, A. MCGINTY, G. L. VILLA, F. FRANCHI, and M. J. DUNN
PreproEndothelin-1 Expression in Human Mesangial Cells: Evidence for a p38 Mitogen-Activated Protein Kinase/Protein Kinases-C--Dependent Mechanism
J. Am. Soc. Nephrol., June 1, 2001; 12(6): 1137 - 1150.
[Abstract] [Full Text]


Home page
Mol. Endocrinol.Home page
E. T. Maizels, A. Mukherjee, G. Sithanandam, C. A. Peters, J. Cottom, K. E. Mayo, and M. Hunzicker-Dunn
Developmental Regulation of Mitogen-Activated Protein Kinase-Activated Kinases-2 and -3 (MAPKAPK-2/-3) in Vivo during Corpus Luteum Formation in the Rat
Mol. Endocrinol., May 1, 2001; 15(5): 716 - 733.
[Abstract] [Full Text]


Home page
Circ. Res.Home page
K. Yamashita, J. Kajstura, D. J. Discher, B. J. Wasserlauf, N. H. Bishopric, P. Anversa, and K. A. Webster
Reperfusion-Activated Akt Kinase Prevents Apoptosis in Transgenic Mouse Hearts Overexpressing Insulin-Like Growth Factor-1
Circ. Res., March 30, 2001; 88(6): 609 - 614.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
B. Aghdasi, K. Ye, A. Resnick, A. Huang, H. C. Ha, X. Guo, T. M. Dawson, V. L. Dawson, and S. H. Snyder
FKBP12, the 12-kDa FK506-binding protein, is a physiologic regulator of the cell cycle
PNAS, February 15, 2001; (2001) 41614198.
[Abstract] [Full Text]


Home page
Am. J. Physiol. Gastrointest. Liver Physiol.Home page
A. Todisco, S. Ramamoorthy, T. Witham, N. Pausawasdi, S. Srinivasan, C. J. Dickinson, F. K. Askari, and D. Krametter
Molecular mechanisms for the antiapoptotic action of gastrin
Am J Physiol Gastrointest Liver Physiol, February 1, 2001; 280(2): G298 - G307.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Cell Physiol.Home page
S. C. Dahl, J. S. Handler, and H. M. Kwon
Hypertonicity-induced phosphorylation and nuclear localization of the transcription factor TonEBP
Am J Physiol Cell Physiol, February 1, 2001; 280(2): C248 - C253.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Heart Circ. Physiol.Home page
S. Schneider, W. Chen, J. Hou, C. Steenbergen, and E. Murphy
Inhibition of p38 MAPK {alpha}/{beta} reduces ischemic injury and does not block protective effects of preconditioning
Am J Physiol Heart Circ Physiol, February 1, 2001; 280(2): H499 - H508.
[Abstract] [Full Text] [PDF]


Home page
JCBHome page
H. Reuveni, T. Geiger, B. Geiger, and A. Levitzki
Reversal of the Ras-induced Transformed Phenotype by HR12, a Novel Ras Farnesylation Inhibitor, Is Mediated by the Mek/Erk Pathway
J. Cell Biol., December 11, 2000; 151(6): 1179 - 1192.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
S. F. Steinberg
The Cellular Actions of {beta}-Adrenergic Receptor Agonists : Looking Beyond cAMP
Circ. Res., December 8, 2000; 87(12): 1079 - 1082.
[Full Text] [PDF]


Home page
FASEB J.Home page
A. T. SAURIN, J. L. MARTIN, R. J. HEADS, C. FOLEY, J. W. MOCKRIDGE, M. J. WRIGHT, Y. WANG, and M. S. MARBER
The role of differential activation of p38-mitogen-activated protein kinase in preconditioned ventricular myocytes
FASEB J, November 1, 2000; 14(14): 2237 - 2246.
[Abstract] [Full Text]


Home page
BloodHome page
S. Verploegen, J.-W. J. Lammers, L. Koenderman, and P. J. Coffer
Identification and characterization of CKLiK, a novel granulocyte Ca++/calmodulin-dependent kinase
Blood, November 1, 2000; 96(9): 3215 - 3223.
[Abstract] [Full Text] [PDF]


Home page
EndocrinologyHome page
R. A. Frost, G. J. Nystrom, and C. H. Lang
Stimulation of Insulin-Like Growth Factor Binding Protein-1 Synthesis by Interleukin-1{beta}: Requirement of the Mitogen-Activated Protein Kinase Pathway
Endocrinology, September 1, 2000; 141(9): 3156 - 3164.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
P. Ping and E. Murphy
Role of p38 Mitogen-Activated Protein Kinases in Preconditioning : A Detrimental Factor or a Protective Kinase?
Circ. Res., May 12, 2000; 86(9): 921 - 922.
[Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. Pomerance, H.-B. Abdullah, S. Kamerji, C. Correze, and J.-P. Blondeau
Thyroid-stimulating Hormone and Cyclic AMP Activate p38 Mitogen-activated Protein Kinase Cascade. INVOLVEMENT OF PROTEIN KINASE A, Rac1, AND REACTIVE OXYGEN SPECIES
J. Biol. Chem., December 15, 2000; 275(51): 40539 - 40546.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
R. A. Ward, M. Nakamura, and K. R. McLeish
Priming of the Neutrophil Respiratory Burst Involves p38 Mitogen-activated Protein Kinase-dependent Exocytosis of Flavocytochrome b558-containing Granules
J. Biol. Chem., November 17, 2000; 275(47): 36713 - 36719.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
X. Zhen, L. Wei, Q. Wu, Y. Zhang, and Q. Chen
Mitogen-activated Protein Kinase p38 Mediates Regulation of Chondrocyte Differentiation by Parathyroid Hormone
J. Biol. Chem., February 9, 2001; 276(7): 4879 - 4885.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
Y. Tamir and E. Bengal
Phosphoinositide 3-Kinase Induces the Transcriptional Activity of MEF2 Proteins during Muscle Differentiation
J. Biol. Chem., October 27, 2000; 275(44): 34424 - 34432.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
M. J. Rane, P. Y. Coxon, D. W. Powell, R. Webster, J. B. Klein, W. Pierce, P. Ping, and K. R. McLeish
p38 Kinase-dependent MAPKAPK-2 Activation Functions as 3-Phosphoinositide-dependent Kinase-2 for Akt in Human Neutrophils
J. Biol. Chem., January 26, 2001; 276(5): 3517 - 3523.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
L. V. Madrid, M. W. Mayo, J. Y. Reuther, and A. S. Baldwin Jr.
Akt Stimulates the Transactivation Potential of the RelA/p65 Subunit of NF-kappa B through Utilization of the Ikappa B Kinase and Activation of the Mitogen-activated Protein Kinase p38
J. Biol. Chem., May 25, 2001; 276(22): 18934 - 18940.
[Abstract] [Full Text] [PDF]


Home page
J. Biol. Chem.Home page
L. Wang, I. Gout, and C. G. Proud
Cross-talk between the ERK and p70 S6 Kinase (S6K) Signaling Pathways. MEK-DEPENDENT ACTIVATION OF S6K2 IN CARDIOMYOCYTES
J. Biol. Chem., August 24, 2001; 276(35): 32670 - 32677.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
B. Aghdasi, K. Ye, A. Resnick, A. Huang, H. C. Ha, X. Guo, T. M. Dawson, V. L. Dawson, and S. H. Snyder
FKBP12, the 12-kDa FK506-binding protein, is a physiologic regulator of the cell cycle
PNAS, February 27, 2001; 98(5): 2425 - 2430.
[Abstract] [Full Text] [PDF]


Home page
Am. J. Physiol. Cell Physiol.Home page
O. Nahm, S. K. Woo, J. S. Handler, and H. M. Kwon
Involvement of multiple kinase pathways in stimulation of gene transcription by hypertonicity
Am J Physiol Cell Physiol, January 1, 2002; 282(1): C49 - C58.
[Abstract] [Full Text] [PDF]


Home page
Circ. Res.Home page
J. L. Martin, M. Avkiran, R. A. Quinlan, P. Cohen, and M. S. Marber
Antiischemic Effects of SB203580 Are Mediated Through the Inhibition of p38{alpha} Mitogen-Activated Protein Kinase: Evidence From Ectopic Expression of an Inhibition-Resistant Kinase
Circ. Res., October 26, 2001; 89(9): 750 - 752.
[Abstract] [Full Text] [PDF]


This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Submit a Letter to Editor
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowRequest Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Lali, F. V.
Right arrow Articles by Foxwell, B. M. J.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Lali, F. V.
Right arrow Articles by Foxwell, B. M. J.
Social Bookmarking
 Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati  
What's this?


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 All ASBMB Journals   Molecular and Cellular Proteomics 
 Journal of Lipid Research   ASBMB Today 
Copyright © 2000 by the American Society for Biochemistry and Molecular Biology.
Advertisement
spacer
Advertisement
Advertisement