Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

α-Actinin-4/FSGS1 is required for Arp2/3-dependent actin assembly at the adherens junction

α-Actinin-4/FSGS1 is required for Arp2/3-dependent actin assembly at the adherens junction We have developed an in vitro assay to study actin assembly at cadherin-enriched cell junctions. Using this assay, we demonstrate that cadherin-enriched junctions can polymerize new actin filaments but cannot capture preexisting filaments, suggesting a mechanism involving de novo synthesis. In agreement with this hypothesis, inhibition of Arp2/3-dependent nucleation abolished actin assembly at cell–cell junctions. Reconstitution biochemistry using the in vitro actin assembly assay identified α-actinin-4/focal segmental glomerulosclerosis 1 (FSGS1) as an essential factor. α-Actinin-4 specifically localized to sites of actin incorporation on purified membranes and at apical junctions in Madin–Darby canine kidney cells. Knockdown of α-actinin-4 decreased total junctional actin and inhibited actin assembly at the apical junction. Furthermore, a point mutation of α-actinin-4 (K255E) associated with FSGS failed to support actin assembly and acted as a dominant negative to disrupt actin dynamics at junctional complexes. These findings demonstrate that α-actinin-4 plays an important role in coupling actin nucleation to assembly at cadherin-based cell–cell adhesive contacts. Submitted: 22 March 2011 Accepted: 6 December 2011 This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms ). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ ). http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png The Journal of Cell Biology Rockefeller University Press

α-Actinin-4/FSGS1 is required for Arp2/3-dependent actin assembly at the adherens junction

Tang, Vivian W.; Brieher, William M.
The Journal of Cell Biology , Volume 196 (1): 115 – Jan 9, 2012
Download PDF
16 pages

Loading next page...
 
/lp/rockefeller-university-press/actinin-4-fsgs1-is-required-for-arp2-3-dependent-actin-assembly-at-the-EoEIePAU0l

References

References for this paper are not available at this time. We will be adding them shortly, thank you for your patience.

Publisher
Rockefeller University Press
Copyright
© 2012 Tang and Brieher
ISSN
0021-9525
eISSN
1540-8140
DOI
10.1083/jcb.201103116
pmid
22232703
Publisher site
See Article on Publisher Site

Abstract

We have developed an in vitro assay to study actin assembly at cadherin-enriched cell junctions. Using this assay, we demonstrate that cadherin-enriched junctions can polymerize new actin filaments but cannot capture preexisting filaments, suggesting a mechanism involving de novo synthesis. In agreement with this hypothesis, inhibition of Arp2/3-dependent nucleation abolished actin assembly at cell–cell junctions. Reconstitution biochemistry using the in vitro actin assembly assay identified α-actinin-4/focal segmental glomerulosclerosis 1 (FSGS1) as an essential factor. α-Actinin-4 specifically localized to sites of actin incorporation on purified membranes and at apical junctions in Madin–Darby canine kidney cells. Knockdown of α-actinin-4 decreased total junctional actin and inhibited actin assembly at the apical junction. Furthermore, a point mutation of α-actinin-4 (K255E) associated with FSGS failed to support actin assembly and acted as a dominant negative to disrupt actin dynamics at junctional complexes. These findings demonstrate that α-actinin-4 plays an important role in coupling actin nucleation to assembly at cadherin-based cell–cell adhesive contacts. Submitted: 22 March 2011 Accepted: 6 December 2011 This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms ). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/ ).

Journal

The Journal of Cell Biology – Rockefeller University Press

Published: Jan 9, 2012

There are no references for this article.