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

J. Biol. Chem., Vol. 282, Issue 20, 15159-15169, May 18, 2007

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 282/20/15159    most recent M608800200v1 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 Google Scholar Google Scholar Articles by Yatsenko, A. S. Articles by Ruohola-Baker, H. Search for Related Content PubMed PubMed Citation Articles by Yatsenko, A. S. Articles by Ruohola-Baker, H. Social Bookmarking                      What's this?

A Putative Src Homology 3 Domain Binding Motif but Not the C-terminal Dystrophin WW Domain Binding Motif Is Required for Dystroglycan Function in Cellular Polarity in Drosophila^*

Andriy S. Yatsenko¹, Elizabeth E. Gray¹, Halyna R. Shcherbata, Larissa B. Patterson, Vanita D. Sood, Mariya M. Kucherenko, David Baker, and Hannele Ruohola-Baker²

From the Department of Biochemistry, University of Washington, Seattle, Washington 98195 and Ivan Franko National University, Hrushevskogo Str. 4, Lviv 79005, Ukraine

The conserved dystroglycan-dystrophin (Dg·Dys) complex connects the extracellular matrix to the cytoskeleton. In humans as well as Drosophila, perturbation of this complex results in muscular dystrophies and brain malformations and in some cases cellular polarity defects. However, the regulation of the Dg·Dys complex is poorly understood in any cell type. We now find that in loss-of-function and overexpression studies more than half (34 residues) of the Dg proline-rich conserved C-terminal regions can be truncated without significantly compromising its function in regulating cellular polarity in Drosophila. Notably, the truncation eliminates the WW domain binding motif at the very C terminus of the protein thought to mediate interactions with dystrophin, suggesting that a second, internal WW binding motif can also mediate this interaction. We confirm this hypothesis by using a sensitive fluorescence polarization assay to show that both WW domain binding sites of Dg bind to Dys in humans (K_d = 7.6 and 81 µM, respectively) and Drosophila (K_d = 16 and 46 µM, respectively). In contrast to the large deletion mentioned above, a single proline to an alanine point mutation within a predicted Src homology 3 domain (SH3) binding site abolishes Dg function in cellular polarity. This suggests that an SH3-containing protein, which has yet to be identified, functionally interacts with Dg.

Received for publication, September 12, 2006 , and in revised form, February 20, 2007.

^* This work was supported by NASA Grant (to E. E. G.), by an American Heart Association fellowship (to H. R. S.), Civilian Research and Development Foundation (to A. S. Y., H. R. S., and H. R.-B.), and by grants from the National Institutes of Health (to D. B., and H. R.-B.), and MDA (to H. R.-B.). 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 Results, Experimental Procedures, and Figs. S1 and S2.

¹ Both authors contributed equally to the publication.

² To whom correspondence should be addressed: Dept. of Biochemistry, University of Washington, HSB J-591, Box 357350 Seattle, WA 98195. Tel.: 206-543-8468; E-mail: hannele{at}u.washington.edu.

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