Differential Regulation of Pyk2 and Focal Adhesion Kinase (FAK)
THE C-TERMINAL DOMAIN OF FAK CONFERS RESPONSE TO CELL ADHESION*
- Chuanhai Zheng‡,
- Zheng Xing,
- Z. Christine Bian,
- Chunmei Guo,
- Aysegul Akbay,
- Laurie Warner and
- Jun-Lin Guan§
- From the Cancer Biology Laboratories, Department of Pathology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853
Abstract
Pyk2 is a recently described cytoplasmic tyrosine kinase that is related to focal adhesion kinase (FAK) and can be activated by a variety of stimuli that elevate intracellular calcium. In this report, we showed that Pyk2 and FAK tyrosine phosphorylation are regulated differentially by integrin-mediated cell adhesion and soluble factors both in rat aortic smooth muscle cells, which express endogenous Pyk2 and FAK, and in transfected Chinese hamster ovary cells. We also found that Pyk2 is diffusely present throughout the cytoplasm, while FAK is localized in focal contacts as expected, suggesting that the different localization may account for their differential regulation. By analyzing a chimeric protein contain N-terminal and kinase domains of Pyk2 and C-terminal domain of FAK, we provided evidence that the distinctive C-terminal domains of Pyk2 and FAK were responsible for their differential regulation by integrins and soluble stimuli as well as their subcellular localization. Finally, we correlated FAK, Pyk2, and the chimeric protein binding to talin, but not paxillin, with their regulation by integrins and focal contact localization. These results demonstrate that the distinctive C-terminal domain of Pyk2 and FAK confer their differential regulation by different subcellular localization and association with the cytoskeletal protein talin.
Footnotes
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↵* This work was supported in part by National Institutes of Health Grant R01GM52890 (to J.-L. G.).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.
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↵‡ Supported in part by National Institutes of Health Training Grant T32CA09682 during the course of this work.
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↵§ To whom correspondence should be addressed. Tel.: 607-253-3586; Fax: 607-253-3708.
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↵1 The abbreviations used are: Pyk2, proline-rich tyrosine kinase 2; FAK, focal adhesion kinase; FN, fibronectin; RASM, rat aortic smooth muscle; HA, hemagglutinin; PLL, poly-l-lysine; DMEM, Dulbecco’s modified Eagle’s medium; FBS, fetal bovine serum; CHO, Chinese hamster ovary; GST, glutathioneS-transferase; PDGF, platelet-derived growth factor; PAGE, polyacrylamide gel electrophoresis; phosphate-buffered saline.
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↵2 Z. Xing, C. Zheng, Z. C. Bian, L. Warner, and J. L. Guan, unpublished results.
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- Received September 30, 1997.
- Revision received November 5, 1997.
- The American Society for Biochemistry and Molecular Biology, Inc.
