|
|
|
|||||||
|
|||||||||
(Received for publication, December 11, 1995, and in revised form, May 21, 1996)
From the Endocrinology-Reproductive Physiology Program, University
of Wisconsin, Madison, Wisconsin 53706
Previously, our laboratory has shown that
prolactin (PRL) inhibits epidermal growth factor (EGF)-induced DNA
synthesis. One pathway for the initiation of DNA synthesis is
EGF-receptor (EGF-R) signaling through Ras and mitogen-activated
protein kinase (MAPK). To determine the effects of PRL on EGF-induced
MAPK activation and phosphorylation, MAPK or phosphotyrosine (Tyr(P))
was immunoprecipitated from normal murine mammary epithelial (NMuMG)
cells treated with PRL (100 ng/ml) and/or EGF (10 ng/ml) for 10-min
periods. EGF-induced phosphorylation and activation were then examined
by Western analysis and a myelin basic protein (MBP)-specific kinase
assay. The p42 isoform of MAPK showed a distinct decrease in activity
and phosphorylation when cells were treated with PRL. Concluding that
PRL affects EGF signaling upstream of MAPK, we examined the
effect of PRL on EGF-induced Ras activity. NMuMG cells were incubated
with [32P]orthophosphoric acid, treated as described
above, immunoprecipitated with an antibody specific to Ras, and
nucleotides were eluted and separated by TLC. Ras activity as measured
by GTP:GDP ratio was increased by EGF, but not by PRL. Additionally,
PRL in combination with EGF abolished the ability of EGF to induce Ras
activity. Those studies suggest that PRL alters the EGF signaling
pathway upstream of Ras. Because Ras activation by EGF involves
EGF-stimulated association of EGF-R with Grb2, the EGF-R was
immunoprecipitated and a Western blot was probed for Grb2. As expected
we found that EGF stimulated an association of EGF-R with Grb2, PRL,
however, blocked this association. When we looked at the ability of Shc
to associate with the EGF-R, we found that PRL and EGF had little
effect on this association. The studies demonstrate that PRL either
directly or indirectly inhibits the ability of EGF to induce EGF-R
association with Grb2, to activate Ras, and to activate and
phosphorylate MAPK.
Volume 271, Number 35,
Issue of August 30, 1996
pp. 21574-21578
©1996 by The American Society for Biochemistry and Molecular Biology, Inc.
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  R. S. Muraoka-Cook, M. Sandahl, D. Hunter, L. Miraglia, and H. S. Earp III Prolactin and ErbB4/HER4 Signaling Interact via Janus Kinase 2 to Induce Mammary Epithelial Cell Gene Expression Differentiation Mol. Endocrinol., October 1, 2008; 22(10): 2307 - 2321. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. K. Halder, G. Anumanthan, R. Maddula, J. Mann, A. Chytil, A. L. Gonzalez, M. K. Washington, H. L. Moses, R. D. Beauchamp, and P. K. Datta Oncogenic Function of a Novel WD-Domain Protein, STRAP, in Human Carcinogenesis. Cancer Res., June 15, 2006; 66(12): 6156 - 6166. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. M. Arendt, T. A. Rose-Hellekant, E. P. Sandgren, and L. A. Schuler Prolactin Potentiates Transforming Growth Factor {alpha} Induction of Mammary Neoplasia in Transgenic Mice Am. J. Pathol., April 1, 2006; 168(4): 1365 - 1374. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. G. Sheffield and J. J. Gavinski Proteomics Methods for Probing Molecular Mechanisms in Signal Transduction J Dairy Sci, July 1, 2003; 86(13_suppl): E115 - 124. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. G. Sheffield and J. J. Gavinski Proteomics methods for probing molecular mechanisms in signal transduction J Anim Sci, March 1, 2003; 81(suppl_3): 48 - 57. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. K. G. Crean, D. Finlay, M. Murphy, C. Moss, C. Godson, F. Martin, and H. R. Brady The Role of p42/44 MAPK and Protein Kinase B in Connective Tissue Growth Factor Induced Extracellular Matrix Protein Production, Cell Migration, and Actin Cytoskeletal Rearrangement in Human Mesangial Cells J. Biol. Chem., November 8, 2002; 277(46): 44187 - 44194. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. L. Schwertfeger, S. Hunter, L. E. Heasley, V. Levresse, R. P. Leon, J. DeGregori, and S. M. Anderson Prolactin Stimulates Activation of c-jun N-Terminal Kinase (JNK) Mol. Endocrinol., October 1, 2000; 14(10): 1592 - 1602. [Abstract] [Full Text]
|
|
|
|
 |
|
 J. Boerner, M. McManus, G. Martin, and N. Maihle Ras-independent oncogenic transformation by an EGF-receptor mutant J. Cell Sci., January 3, 2000; 113(6): 935 - 942. [Abstract] [PDF]
|
|
|
|
|
|
V. J. Quijano Jr. and L. G. Sheffield Prolactin Decreases Epidermal Growth Factor Receptor Kinase Activity via a Phosphorylation-dependent Mechanism J. Biol. Chem., January 9, 1998; 273(2): 1200 - 1207. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Cheng, I. Zhizhin, R. L. Perlman, and D. Mangoura Prolactin-induced Cell Proliferation in PC12 Cells Depends on JNK but Not ERK Activation J. Biol. Chem., July 21, 2000; 275(30): 23326 - 23332. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. L. Boerner, A. Danielsen, M. J. McManus, and N. J. Maihle Activation of Rho Is Required for Ligand-independent Oncogenic Signaling by a Mutant Epidermal Growth Factor Receptor J. Biol. Chem., January 26, 2001; 276(5): 3691 - 3695. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| All ASBMB Journals | Molecular and Cellular Proteomics |
| Journal of Lipid Research | ASBMB Today |