Evidence That DOCK180 Up-regulates Signals from the CrkII-p130Cas Complex*
- From the ‡Department of Pathology, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo 162-8840, the §First Department of Pathology, Hamamatsu University School of Medicine, 3600 Handa-cho, Hamamatsu 431-3192, and the‖Department of Pathology, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan
Abstract
DOCK180 is one of the two principal proteins bound to the SH3 domain of the adaptor protein CrkII. Here, we have studied the involvement of DOCK180 in integrin signaling. DOCK180 was neither phosphorylated nor bound to CrkII in quiescent NIH 3T3 cells and 3Y1 cells. We found that DOCK180 was phosphorylated and bound to CrkII in NIH 3T3 cells stimulated with integrin and also in 3Y1 cells transformed by v-src or v-crk. The binding of DOCK180 to CrkII correlated with the binding of CrkII to p130Cas, which is a major CrkII SH2 domain-binding protein at focal adhesions. In a reconstitution experiment, expression of DOCK180 induced hyperphosphorylation of p130Cas and a concomitant increase in the amount of CrkII bound to p130Cas. Similarly, binding of DOCK180 to CrkII was also enhanced by the coexpression of p130Cas. Finally, we found that coexpression of p130Cas and CrkII with DOCK180 induced local membrane spreading and accumulation of DOCK180-CrkII-p130Cas complexes at focal adhesions. These findings suggest that DOCK180 positively regulates signaling from integrins to CrkII-p130Cas complexes at focal adhesions.
Footnotes
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↵* This work was supported in part by grants from the Ministry of Education, Science, and Culture, from the Science and Technology Agency, and from the Human Science Foundation, Japan.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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↵¶ Recipient of a research resident fellowship from the Japanese Foundation of AIDS Prevention.
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↵** To whom correspondence should be addressed: Dept. of Pathology, Research Institute, International Medical Center of Japan, 1-21-1 Toyama, Shinjuku-ku, Tokyo 162-8655, Japan. Tel.: 81-3-3202-7181 (ext. 2832); Fax: 81-3-3205-1236; E-mail: mmatsuda{at}ri.imcj.go.jp.
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↵2 E. Kiyokawa and M. Matsuda, unpublished observation.
- Abbreviations:
- EGF
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epidermal growth factor
- PAGE
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polyacrylamide gel electrophoresis.
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- Received February 9, 1998.
- Revision received July 6, 1998.
- The American Society for Biochemistry and Molecular Biology, Inc.
