HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stradal, T. B. Articles by Gimona, M. Search for Related Content PubMed PubMed Citation Articles by Stradal, T. B. Articles by Gimona, M. Social Bookmarking                      What's this?

J Biol Chem, Vol. 274, Issue 44, 31593-31596, October 29, 1999

Ca²⁺-dependent Association of S100A6 (Calcyclin) with the Plasma Membrane and the Nuclear Envelope^*

Theresia B. Stradal and Mario Gimona

From the Department of Cell Biology, Institute of Molecular Biology, Austrian Academy of Sciences, Billrothstrasse 11, A-5020 Salzburg, Austria

	ABSTRACT

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS AND DISCUSSION REFERENCES

Expression of S100A6 (Calcyclin), a member of the S100 family and of Zn²⁺-binding proteins is elevated in a number of malignant tumors. In vitro the protein associates with several actin-binding proteins and annexins in a Ca²⁺-dependent manner. We have now studied the subcellular localization of S100A6 using a new, specific monoclonal antibody. Immunofluorescence microscopy of unfixed, ultrathin, frozen sections demonstrated a dual localization of S100A6 at the nuclear envelope and the plasma membrane of porcine smooth muscle only in the presence of Ca²⁺. The same localization was found by immunofluorescence and immunogold electron microscopy as well as by confocal laser scanning microscopy with cultured, fixed, human CaKi-2 and porcine ST interphase cells. Upon cell division, however, S100A6 was found exclusively in the cytoplasm. Cell fractionation studies showed that S100A6 was present in the microsomal fraction in the presence of Ca²⁺ and was released from this fraction by the addition of EGTA/EDTA but not by Triton X-100. The data demonstrate that S100A6 is localized both at the plasma membrane and the nuclear envelope in vivo and suggest a Ca²⁺-dependent interaction with annexins or other components of the nuclear envelope.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS AND DISCUSSION REFERENCES

Because calcium plays a crucial role in the regulation of several nuclear functions (1, 2), a strong interest exists in identifying Ca²⁺-binding proteins involved in the perception and transduction of signals involved in cell cycle control and cell death. The S100 family comprises 16 closely related members, 13 of which form a gene cluster in the epidermal differentiation complex of chromosome 1 in humans (3). S100 proteins consist of two Ca²⁺-binding EF-hands and short individual N and C termini. The first EF-hand is conserved among the S100 family and the second EF-hand follows the canonical consensus. Almost all S100 proteins form stable homo- or heterodimers and several members have been shown to bind Zn²⁺ in addition to Ca²⁺ in vitro (4). A subclass of EF-hand Ca²⁺-binding proteins forming the large S100 protein family has attracted substantial interest in the last decade due to their tissue- and cell type-specific expression patterns and their involvement in several diseases (5). The S100 gene products play a role in multiple proliferation- and differentiation-related events and appear to be involved in autoimmune diseases and cancer (6). S100B is predominantly expressed in brain and has been implicated in Alzheimer's disease, epilepsy, and neurodegenerative symptoms commonly associated with Down Syndrome (7). S100A7 is overexpressed in psoriatic lesions (8), and the S100A8/A9 (MRP8/MRP14) heterodimer plays a role in inflammation and cystic fibrosis (9) (for review see Ref. 6). In contrast to the above, S100A2 is down-regulated in breast cancer and the promotor is activated upon the interaction with wild-type p53 (10). Thus, S100A2 was suggested to be a tumor suppressor-related gene.

S100A6 (calcyclin) was first identified by molecular cloning of the growth factor-inducible gene 2A9 (11). Its expression is elevated in response to growth factor-stimulated proliferation of quiescent fibroblasts, indicating a role in cell cycle progression (12). Further studies showed that this elevation in expression is mediated by a growth factor-responsive element in the promotor region of S100A6 (13) and peaks in the transition from G₀- to S-phase in serum-stimulated quiescent smooth muscle cells (14). S100A6 was also found to be overexpressed in several tumors like acute myeloid leukemia (11) and neuroblastoma (15), and also in a variety of melanoma cell lines (16). Overexpression of S100A6 correlates with the metastatic behavior in nude mice and an up-regulated expression has also been observed in wound healing after corneal injury (17). S100A6 was additionally identified and purified from murine Ehrlich ascites tumor cells (18) and Gou et al. (19) described a correlation between the expression of S100A6 and the metastatic behavior of Ras-transformed NIH 3T3 fibroblasts. In benign tissues, S100A6 is expressed predominantly in fibroblasts and epithelial cells (20) but is also present in neuronal and smooth muscle cells. To elucidate the in vivo function(s) of S100A6 recent efforts focused on the identification of cellular binding partners and the metal-binding characteristics (21). Several in vitro studies revealed Ca²⁺-dependent interactions with actin binding proteins like caldesmon (22), tropomyosin (23), and calponin (24). More recently a novel protein of yet unknown function, termed p30 or CaCYBP, has been reported to bind to S100A6 in vitro (25). In addition, members of the annexin family were shown to interact with S100A6 in a Ca²⁺-dependent manner. Thus, affinity chromatography using immobilized calcyclin revealed an interaction with annexin II and annexin VI (26). The interaction of S100A6 with annexin XI has been studied in more detail, and the binding sites on both molecules have been mapped (27). Notably, annexin XI has been reported to target to the nucleus and to display a distinct localization during mitosis (28).

The localization of S100A6 has been also studied in transformed (15, 29) or normal tissues (20, 30), and in cultured smooth muscle cells (31) using a polyclonal antibody. In this study we have reinvestigated the Ca²⁺-dependent subcellular localization of S100A6 using a novel highly specific monoclonal antibody and show that the protein localizes to the plasma membrane and the nuclear envelope of smooth and nonmuscle cells.

	EXPERIMENTAL PROCEDURES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS AND DISCUSSION REFERENCES

All chemicals were from Merck with the exception of HEPES and Triton X-100 (Sigma), fetal bovine serum (HyClone), Dulbecco's modified Eagle's medium and minimal essential medium (Life Technologies).

Antibodies-- Monoclonal anti-porcine calcyclin (clone CACY-100) was from Sigma.

Ultrathin Frozen Sections-- Fresh porcine stomach smooth muscle tissue was excised in 2 × 2 × 30 mm strips and submerged in buffer containing 20 mM imidazole, pH 7.0, 150 mM NaCl, 5 mM MgCl₂, 5% (v/v) glycerol, 1 mM NaN₃, 1 mM phenylmethylsulfonyl fluoride, 10 µg/ml leupeptin-pepstatin (Roche), and 2 M sucrose as cryoprotectant at 4 °C overnight. Muscle strips were then mounted onto aluminum cryopins (Reichert) and frozen in liquid nitrogen. Cryosections of 5-8 µm were cut using a Reichert-Jung FC4E cryo-ultramicrotome. Sections were then transferred to silanized coverslips, dried for 1 h at room temperature and subjected to immunofluorescence staining.

Cell Culture and Immunofluorescence Microscopy-- Porcine testis (ST) and human CaKi-2 cells were cultured in Dulbecco's modified Eagle's medium supplemented with 10% fetal bovine serum at 37 °C and 5% CO₂. For immunofluorescence microscopy, cells were grown on ethanol/HCl-washed 15-mm glass coverslips. Cells on coverslips were rinsed in HBS¹ (10 mM HEPES, pH 7.4, 135 mM NaCl, 15 mM KCl, 5 mM MgCl₂), fixed for 20 min with 3.7% paraformaldehyde in HBS and permeabilized with 0.3% Triton X-100 in 3.7% paraformaldehyde in HBS for 5 min. All steps were carried out in the presence of either 2 mM CaCl₂, 2 mM ZnCl₂, or 5 mM EGTA. After blocking with 1 mg/ml bovine serum albumin and 5% donor horse serum in HBS for 30 min, cells were incubated with monoclonal anti-S100A6 antibody (clone CACY-100), followed by incubation with secondary Cy-3-labeled (Sigma) or biotinylated (Dako) goat anti-mouse IgG antibody and Cy-2 streptavidin (Fluorolink). Coverslips were washed and mounted in Gelvatol containing 2.5 mg/ml n-propylgallate. All steps were carried out in the presence of either 2 mM CaCl₂ or 5 mM EGTA. Fluorescent images were recorded on a Zeiss Axiophot using a 63× (nominal aperture 1.4) oil immersion lens and Kodak P3200 Tmax film. Confocal microscopy was performed on a Bio-Rad MRC-1024 model using a Zeiss 63× (nominal aperture 1.2) C-apochromat water immersion lens.

Cell Fractionation, Electrophoresis, and Western Blotting-- Cells (porcine ST and human CaKi-2) were grown to 90% confluence in 10-cm tissue culture Petri dishes (Falcon), washed in HBS and harvested in 2 ml of HBS with a tissue culture scraper. For harvesting the cells and all following steps, the HBS contained either 2 mM CaCl₂ or 5 mM EGTA, with or without 0.5% Triton X-100. The suspension was homogenized with a glass-glass tissue grinder and fractionated by ultracentrifugation for 30 min at 100,000 × g (Sorvall, RC M150 GX) at 4 °C. The pellet was washed by resuspension in HBS and ultracentrifugation was repeated. All samples were precipitated with methanol/chloroform following the method of Wessel and Flugge (32) and resuspended in SDS sample buffer, and an equivalent of 2 cm² of cells was applied to the gel. Analytical SDS gel electrophoresis on 10-26% gradient polyacrylamide mini-slab gels and Western blotting onto nitrocellulose (Hybond, Amersham Pharmacia Biotech) was performed as described elsewere (33). Transferred proteins reactive with the monoclonal anti-S100A6 antibody were visualized using horseradish peroxidase-coupled secondary antibodies and the ECL chemiluminescence system (Amersham Pharmacia Biotech).

Electron Microscopy-- Nuclei of cultured pig ST cells were isolated as described by Kihlmark and Hallberg (34), resuspended in HBS containing phenylmethylsulfonyl fluoride, pepstatin-leupeptin, and 0.05% Triton X-100, incubated on ice for 5 min, and pelleted by centrifugation. The pellet was resuspended in HBS containing 1 mg/ml bovine serum albumin and incubated with the monoclonal anti-S100A6 antibody for 1 h at room temperature. After washing the nuclei 3 times in HBS they were incubated with a 10-nm gold-labeled secondary antibody (BioCell) for 45 min at room temperature, washed 3 times and fixed in 3.7% paraformaldehyde , 2.5% glutaraldehyde in HBS for 15 min. The blocks were dehydrated in ethanol and embedded in Araldite (TAAB). Ultrathin sections were stained with uranyl acetate and lead citrate and viewed in a Zeiss EM 10A electron microscope.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS AND DISCUSSION REFERENCES

A monoclonal antibody specific for S100A6 was generated as described earlier (35) using porcine smooth muscle S100 proteins as the antigen. Clone CACY-100 specifically recognizes S100A6 but not S100A2 or S100b on Western blots of whole cell and tissue extracts (Fig. 1).

View larger version (74K): [in this window] [in a new window]   Fig. 1.   Specificity of monoclonal anti-S100A6 antibody. Coomassie Blue-stained polyacrylamide gel electrophoresis gel (A) and corresponding Western blot (B) showing the reactivity of monoclonal antibody clone CACY-100. The antibody specifically recognizes recombinant (lane 1) and native porcine S100A6 (lane 9), detects S100A6 in whole cell extracts of porcine ST (lane 3), porcine LLC PK1 (lane 4), or human CaKi-2 cells (lane 5), and in tissue extracts of porcine stomach (lane 6) and porcine uterus (lane 7) smooth muscle but is not reactive with either recombinant S100A2 (lane 2) or native S100b from bovine brain (lane 8). Note the reactivity of the antibody with both monomer (M) and the stable dimer (D) in purified native S1006 (lane 9). Position of molecular weight markers is indicated in panel A.

We first determined the subcellular localization of S100A6 in unfixed, frozen sections of porcine stomach smooth muscle. In the presence of Ca²⁺, S100A6 displayed a dual localization, on the plasma membrane and in the nucleus. Longitudinal sections revealed an association along thin thread-like structures (Fig. 2A), which correlated with the punctate pattern around the cell periphery seen in cross sections (Fig. 2B). Labeling in the nucleus was confirmed by counterstaining for nucleic acids and higher resolution images revealed a ring-like structure, indicating that S100A6 is localized at the nuclear envelope, but not inside the nucleus (Fig. 2C). Incubation of unfixed tissue sections with buffer containing chelating agents resulted in the complete loss of the fluorescent signal (data not shown).

View larger version (59K): [in this window] [in a new window]   Fig. 2.   Localization of S100A6 in porcine smooth muscle. Unfixed ultrathin frozen longitudinal sections (A) and cross sections (B) stained with antibody CACY-100 in the presence of Ca2+. C, higher contrast image of a cross section reveals concentration of S100A6 around the nuclear envelope.

These data suggested that S100A6 colocalizes with two membranous cellular compartments, namely the plasma membrane and the nuclear envelope of smooth muscle cells in a Ca²⁺-dependent manner. To support the results obtained with unfixed tissue sections, we next studied the distribution of S100A6 in cultured porcine ST cells fixed and labeled both in the presence or absence of divalent cations. In the presence of Ca²⁺, staining of the plasma membrane was observed in cells extracted with 0.1% Triton X-100 (Fig. 3A). When the Triton X-100 concentration was increased to 0.3%, localization at the plasma membrane was lost and a weak cytoplasmic distribution in addition to a strong concentration in the nucleus was observed. Notably, in the presence of Zn²⁺, S100A6 localization was indistinguishable from that seen in cells stained in the absence of both Ca²⁺ and EGTA/EDTA (Fig. 3B). In the presence of chelating agents like EGTA and EDTA S100A6 localization was detected only in the nucleus (Fig. 3C). Identical results were obtained in the human cell line CaKi-2 indicating that the observed localization pattern reflects the position of endogenous S100A6 (not shown), and in agreement with these data Brink et al. (29) and Mandinova et al. (31) likewise reported partial nuclear localization of S100A6 in human cells and tissues. In mitotic cells, S100A6 is distributed throughout the cytoplasm but is absent from regions of condensed chromatin (Fig. 3B, arrowheads). Staining of mitotic and interphase cells using an anti-lamin A antibody resulted in patterns similar to those obtained with the S100A6 antibody (not shown).

View larger version (62K): [in this window] [in a new window]   Fig. 3.   Immunofluorescence micrographs of fixed cultured porcine ST cells stained with monoclonal CACY-100 antibody. In cells extracted with 0.1% Triton X-100 in the presence of Ca2+, S100A6 is detected along the plasma membrane (A). In contrast, extraction with 0.3% Triton X-100 in the absence of Ca2+ reveals S100A6 localization also in the cytoplasm and more strongly at the nuclear envelope (B). Only the nuclear staining was retained in the presence of EGTA (C). Note the diffuse distribution of S100A6 in mitotic cells (arrowheads in panel C).

Confocal laser scanning microscopy was used to further confirm the dual localization of S100A6 at the plasma membrane and the nuclear envelope. Cells were extracted with 0.1% Triton X-100 in the presence of Ca²⁺ and examined by confocal microscopy in the x-z axis. As seen in Fig. 4, A and B, the antibody CACY-100 revealed the presence of S100A6 at the plasma membrane and to a lesser extent in the cytoplasm. We interpret the lack of fluorescent signal at the nuclear envelope as an indication for the inaccessibility of the antibody epitope under these gentle extraction procedures. This conclusion was supported by the results of sections and three-dimensional reconstructions of confocal images from cells extracted in the presence of 0.3% Triton X-100, which showed a specific association of S100A6 with the nuclear envelope (Fig. 4, C and D).

View larger version (121K): [in this window] [in a new window]   Fig. 4.   Confocal images of porcine ST cells permeabilized with 0.1% Triton X-100 in the presence (A, B) or absence (C, D) of Ca2+. A, confocal section in the x-z axis shows the concentration of S100A6 underneath the plasma membrane. B, three-dimensional reconstruction of the same cell as in A. C, x-z section; D, three-dimensional reconstruction of cells permeabilized with 0.5% Triton X-100 in the presence of EGTA. S100A6 is detected exclusively at the nuclear envelope.

In contrast to the results obtained with unfixed tissue sections, S100A6 remained associated with the nuclear envelope of fixed cultured cells even in the presence of EGTA/EDTA. Together with the observed requirement for increased Triton X-100 concentrations, these data strongly suggest that S100A6 localizes at the inner face of the nuclear envelope and that this binding is mediated via a binding partner, which is sensitive to formaldehyde fixation. We therefore used immunogold electron microscopy on isolated nuclei to further test the hypothesis that S100A6 colocalized with inner structures of the nuclear envelope. The nuclear envelope consists of three compartments, the outer nuclear membrane, the inner membrane, and the lamina. As expected, gold particles were detected exclusively in the space between the outer and the inner nuclear membrane, and in the vicinity of the nuclear lamina (Fig. 5).

View larger version (114K): [in this window] [in a new window]   Fig. 5.   Immunogold electron microscopy of isolated nuclei from porcine ST cell permeabilized with 0.05% Triton X-100 in the presence of Ca2+. In thin sections of embedded nuclei counterstained with osmium tetroxide, the 10-nm gold particles are localized inside the nucleus and in the vicinity of the nuclear lamina (arrows). Arrowheads indicate areas of intact nuclear membranes. Orientation of the two individual nuclei is indicated (nuc).

Both fluorescence and electron microscopy suggested a membrane association of S100A6 requiring the presence Ca²⁺. To further support this conclusion, we carried out cell fractionations. As seen in Fig. 6, S100A6 was detected in the microsomal fraction of cultured porcine ST cells by Western blotting, and this association was strictly Ca²⁺-dependent. S100A6 was released from the pellet upon addition of EGTA/EDTA. In contrast, the addition of 0.5% Triton X-100 to the extraction buffer failed to solubilize S100A6. However, significant amounts of S100A6 were also found in the soluble fraction, in agreement with the results obtained in the microscopic studies. These data also support previous studies by Lesniak and Filipek (36) that demonstrated the Ca²⁺-dependent interaction of S100A6 with microsomal membranes from murine Ehrlich ascites tumor cells.

View larger version (47K): [in this window] [in a new window]   Fig. 6.   Cell fractionation of porcine ST cells. Western blot of cell fractionation extracts probed with the monoclonal antibody CACY-100 reveals that S100A6 is present in the microsomal fraction in the presence of Ca2+. Addition of EGTA to the microsomal pellet quantitatively solubilizes S100A6.

Taken together, our data suggest that S100A6 is located in the cytoplasm and is targeted to two membranous compartments, namely the plasma membrane and the nuclear envelope upon the increase of cytoplasmic Ca²⁺, mediated by yet unidentified signals. The variable extractability of S100A6 associated with the plasma membrane versus the nuclear envelope points to an interaction of S100A6 with two different targets. Interaction with the plasma membrane was strongly dependent on the presence of Ca²⁺ but was lost upon the addition of Triton X-100 despite fixation with paraformaldehyde. The interaction with the Triton X-100 insoluble fraction, i.e. the nuclear envelope, likewise depended on the presence of Ca²⁺, as shown in the cell fractionation experiments and in unfixed tissue sections, but S100A6 remained firmly attached to its putative target after fixation even in the presence of EGTA. In contrast, cytoplasmic S100A6 was extracted in the presence and absence of Ca²⁺ despite prior fixation with formaldehyde. Interestingly, several S100 proteins have been shown recently to interact directly with intermediate filament proteins (37). Thus, the association of S100A6 with the intermediate filaments of the nuclear lamina is plausible.

The potential binding partners for S100A6 that have thus far been identified can be divided into two groups, one comprising several actin-binding proteins, and the second embracing members of the annexin family. In this study we failed to detect any colocalization of S100A6 with actin-rich structures, although an interaction with components of the actin cytoskeleton cannot be ruled out completely. Annexin II and annexin VI were described to interact with S100A6 and have been shown to colocalize with the plasma membrane (38). Barwise and Walker (38) demonstrated that annexin II relocates to granular structures at the plasma membrane, whereas annexin VI adopts a more homogeneous distribution at the plasma membrane in cells treated with the calcium ionophore A23187. More importantly, this group also claimed that the intranuclear portion of annexins IV and V translocates to the nuclear membrane under the same conditions. Likewise, annexin XI displays partial nuclear localization and is one of the potential targets of S100A6. The binding sites of both molecules have been mapped within residues 4-7 in S100A6 (39) and residues 52-59 in annexin XI (27), respectively. Furthermore annexin XI has been reported to alter its localization during mitosis, forming an arc-like structure around the mitotic spindle (28). Our results indicate that S100A6 is localized at multiple discrete sites in the cell including the inner face of the nuclear envelope and that the protein undergoes specific translocations during mitosis. The colocalization of S100A6 with these membranous compartments is strictly dependent on the presence of Ca²⁺ and is likely to correspond to the sites of functionally active S100A6. From these data we therefore suggest an interaction of S100A6 in vivo with members of the annexin family, and in particular with nuclear annexin XI. Moreover, we have shown that refined methods are required to reveal the localization of S100A6 at multiple distinct compartments in the cell. Our further efforts are directed toward characterizing the interaction between S100A6 and annexin XI in vitro and in vivo.

	ACKNOWLEDGEMENTS

We are grateful to Dr. K. I. Anderson (Marie Curie Institute, Oxted, United Kingdom) for confocal microscopy, Prof. J. V. Small for help with electron microscopy and valuable comments on the manuscript, and U. Müller and M. Schmittner for technical assistance and photography.

	FOOTNOTES

^* This work was supported by the Austrian Science Foundation (P-11845).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.

To whom correspondence should be addressed. Tel.: 43-662-63961-19; Fax: 43-662-63961-40; E-mail: mgimona@server1.imolbio.oeaw.ac.at.

	ABBREVIATIONS

The abbreviation used is: HBS, HEPES-buffered saline.

	REFERENCES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS AND DISCUSSION REFERENCES

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				L. M. Orre, M. Pernemalm, J. Lengqvist, R. Lewensohn, and J. Lehtio Up-regulation, Modification, and Translocation of S100A6 Induced by Exposure to Ionizing Radiation Revealed by Proteomics Profiling Mol. Cell. Proteomics, December 1, 2007; 6(12): 2122 - 2131. [Abstract] [Full Text] [PDF]

				L. Farnaes and H. J. Ditzel Dissecting the Cellular Functions of Annexin XI Using Recombinant Human Annexin XI-specific Autoantibodies Cloned by Phage Display J. Biol. Chem., August 29, 2003; 278(35): 33120 - 33126. [Abstract] [Full Text] [PDF]

				A. Tomas and S. E. Moss Calcium- and Cell Cycle-dependent Association of Annexin 11 with the Nuclear Envelope J. Biol. Chem., May 23, 2003; 278(22): 20210 - 20216. [Abstract] [Full Text] [PDF]

				P. J. Adam, R. Boyd, K. L. Tyson, G. C. Fletcher, A. Stamps, L. Hudson, H. R. Poyser, N. Redpath, M. Griffiths, G. Steers, et al. Comprehensive Proteomic Analysis of Breast Cancer Cell Membranes Reveals Unique Proteins with Potential Roles in Clinical Cancer J. Biol. Chem., February 14, 2003; 278(8): 6482 - 6489. [Abstract] [Full Text] [PDF]

				N. Courtois-Coutry, C. Le Moellic, S. Boulkroun, M. Fay, F. Cluzeaud, B. Escoubet, N. Farman, and M. Blot-Chabaud Calcyclin Is an Early Vasopressin-induced Gene in the Renal Collecting Duct. ROLE IN THE LONG TERM REGULATION OF ION TRANSPORT J. Biol. Chem., July 5, 2002; 277(28): 25728 - 25734. [Abstract] [Full Text] [PDF]

				A. Filipek, B. Jastrzebska, M. Nowotny, K. Kwiatkowska, M. Hetman, L. Surmacz, E. Wyroba, and J. Kuznicki Ca2+-dependent Translocation of the Calcyclin-binding Protein in Neurons and Neuroblastoma NB-2a Cells J. Biol. Chem., May 31, 2002; 277(23): 21103 - 21109. [Abstract] [Full Text] [PDF]

				H.-L. Hsieh, B. W. Schafer, J. A. Cox, and C. W. Heizmann S100A13 and S100A6 exhibit distinct translocation pathways in endothelial cells J. Cell Sci., January 8, 2002; 115(15): 3149 - 3158. [Abstract] [Full Text] [PDF]

				T. B. Stradal, H. Troxler, C. W. Heizmann, and M. Gimona Mapping the Zinc Ligands of S100A2 by Site-directed Mutagenesis J. Biol. Chem., April 28, 2000; 275(18): 13219 - 13227. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Stradal, T. B. Articles by Gimona, M. Search for Related Content PubMed PubMed Citation Articles by Stradal, T. B. Articles by Gimona, M. Social Bookmarking                      What's this?