MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
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 arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cary, L. A.
Right arrow Articles by Cooper, J. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cary, L. A.
Right arrow Articles by Cooper, J. A.
Molecular and Cellular Biology, April 2002, p. 2427-2440, Vol. 22, No. 8
0270-7306/02/$04.00+0     DOI: 10.1128/MCB.22.8.2427-2440.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.

Src Catalytic but Not Scaffolding Function Is Needed for Integrin-Regulated Tyrosine Phosphorylation, Cell Migration, and Cell Spreading

Leslie A. Cary,* Richard A. Klinghoffer,,{dagger} Christoph Sachsenmaier,,{ddagger} and Jonathan A. Cooper*

Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109

Received 25 September 2001/ Returned for modification 6 November 2001/ Accepted 16 January 2002

Src family kinases (SFKs) are crucial for signaling through a variety of cell surface receptors, including integrins. There is evidence that integrin activation induces focal adhesion kinase (FAK) autophosphorylation at Y397 and that Src binds to and is activated by FAK to carry out subsequent phosphorylation events. However, it has also been suggested that Src functions as a scaffolding molecule through its SH2 and SH3 domains and that its kinase activity is not necessary. To examine the role of SFKs in integrin signaling, we have expressed various Src molecules in fibroblasts lacking other SFKs. In cells plated on fibronectin, FAK could indeed autophosphorylate at Y397 independently of Src but with lower efficiency than when Src was present. This step was promoted by kinase-inactive Src, but Src kinase activity was required for full rescue. Src kinase activity was also required for phosphorylation of additional sites on FAK and for other integrin-directed functions, including cell migration and spreading on fibronectin. In contrast, Src mutations in the SH2 or SH3 domain greatly reduced binding to FAK, Cas, and paxillin but had little effect on tyrosine phosphorylation or biological assays. Furthermore, our indirect evidence indicates that Src kinase activity does not need to be regulated to promote cell migration and FAK phosphorylation. Although Src clearly plays important roles in integrin signaling, it was not concentrated in focal adhesions. These results indicate that the primary role of Src in integrin signaling is as a kinase. Indirect models for Src function are proposed.

* Corresponding author. Mailing address: Fred Hutchinson Cancer Research Center, 1100 Fairview Ave. N., Mailstop A2-025, P.O. Box 19024, Seattle, WA 98109. Phone: (206) 667-4454. Fax: (206) 667-6522. E-mail address for Jonathan A. Cooper: jcooper{at}fhcrc.org. E-mail address for Leslie A. Cary: lcary{at}fhcrc.org.

{dagger} Present address: CEPTYR, Inc., Bothell, WA 98021.

{ddagger} Present address: ProQinase GmbH, D-79106 Freiburg, Germany.

Molecular and Cellular Biology, April 2002, p. 2427-2440, Vol. 22, No. 8
0022-538X/02/$04.00+0     DOI: 10.1128/MCB.22.8.2427-2440.2002
Copyright © 2002, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 2002 by the American Society for Microbiology. All rights reserved.