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J. Biol. Chem., Vol. 283, Issue 15, 9814-9819, April 11, 2008

This Article Full Text Full Text (PDF) Supplemental Data All Versions of this Article: 283/15/9814    most recent M710475200v1 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 Pasic, L. Articles by Schafer, D. A. Search for Related Content PubMed PubMed Citation Articles by Pasic, L. Articles by Schafer, D. A. Social Bookmarking                      What's this?

Ena/VASP Proteins Capture Actin Filament Barbed Ends^*

Lejla Pasic, Tatyana Kotova, and Dorothy A. Schafer¹

From the Departments of Biology and Cell Biology, University of Virginia, Charlottesville, Virginia 22903

Ena/VASP (vasodialator-stimulated protein) proteins regulate many actin-dependent events, including formation of protrusive structures, fibroblast migration, neurite extension, cell-cell adhesion, and Listeria pathogenesis. In vitro, Ena/VASP activities on actin are complex and varied. They promote actin assembly, protect filaments from cappers, bundle filaments, and inhibit filament branching. To determine the mechanisms by which Ena/VASP proteins regulate actin dynamics at barbed ends, we monitored individual actin filaments growing in the presence of VASP and profilin using total internal reflection fluorescence microscopy. Filament growth was unchanged by VASP, but filaments grew faster in profilin-actin and VASP than with profilin-actin alone. Actin filaments were captured directly by VASP-coated surfaces via interactions with growing barbed ends. End-attached filaments transiently paused but resumed growth after becoming bound to the surface via a filament side attachment. Thus, Ena/VASP proteins promote actin assembly by interacting directly with actin filament barbed ends, recruiting profilin-actin, and blocking capping.

Received for publication, December 23, 2007

^* This work was supported by NIGMS, National Institutes of Health Grant R01-067222 (to D. A. S.). 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 Fig. S1 and supplemental movies S1-S4.

¹ To whom correspondence should be addressed: Dept. of Biology, University of Virginia, Gilmer Hall, McCormick Rd., Charlottesville, VA 22901. Fax: 434-982-5626; E-mail: das9w{at}virginia.edu.

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