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

J. Biol. Chem., Vol. 283, Issue 27, 18685-18693, July 4, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/27/18685    most recent M801274200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted 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 Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Zhang, Z. M. Articles by Zheng, J. J. Search for Related Content PubMed PubMed Citation Articles by Zhang, Z. M. Articles by Zheng, J. J. Social Bookmarking                      What's this?

GIT1 Paxillin-binding Domain Is a Four-helix Bundle, and It Binds to Both Paxillin LD2 and LD4 Motifs^*

Ziwei M. Zhang, Joseph A. Simmerman¹, Cristina D. Guibao, and Jie J. Zheng²

From the Department of Structural Biology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105 and the Department of Molecular Sciences, University of Tennessee Health Science Center, Memphis, Tennessee 38163

The G protein-coupled receptor kinase-interacting protein 1 (GIT1) is a multidomain protein that plays an important role in cell adhesion, motility, cytoskeletal remodeling, and membrane trafficking. GIT1 mediates the localization of the p21-activated kinase (PAK) and PAK-interactive exchange factor to focal adhesions, and its activation is regulated by the interaction between its C-terminal paxillin-binding domain (PBD) and the LD motifs of paxillin. In this study, we determined the solution structure of rat GIT1 PBD by NMR spectroscopy. The PBD folds into a four-helix bundle, which is structurally similar to the focal adhesion targeting and vinculin tail domains. Previous studies showed that GIT1 interacts with paxillin through the LD4 motif. Here, we demonstrated that in addition to the LD4 motif, the GIT1 PBD can also bind to the paxillin LD2 motif, and both LD2 and LD4 motifs competitively target the same site on the PBD surface. We also revealed that paxillin Ser²⁷² phosphorylation does not influence GIT1 PBD binding in vitro. These results are in agreement with the notion that phosphorylation of paxillin Ser²⁷² plays an essential role in regulating focal adhesion turnover.

Received for publication, February 19, 2008 , and in revised form, April 8, 2008.

^* This work was supported, in whole or in part, by National Institutes of Health Grant R01GM069916. This work was also supported by the American Lebanese Syrian Associated Charities. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

The on-line version of this article (available at http://www.jbc.org) contains supplemental Figs. S1–S8.

The atomic coordinates and structure factors (code 2JX0) have been deposited in the Protein Data Bank, Research Collaboratory for Structural Bioinformatics, Rutgers University, New Brunswick, NJ (http://www.rcsb.org/).

¹ Present address: Dept. of Cellular and Molecular Biology, Adam State College, Alamosa, CO 81102.

² To whom correspondence should be addressed: Dept. of Structural Biology, St. Jude Children's Research Hospital, 332 N. Lauderdale St., Memphis, TN 38105. Tel.: 901-495-3168; Fax: 901-495-3032; E-mail: jie.zheng{at}stjude.org.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?