spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online 24 April 2007
doi: 10.1242/jcs.007641

Journal of Cell Science 120, 1779-1790 (2007)
Published by The Company of Biologists 2007
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Supplementary Material
Right arrow All Versions of this Article:
jcs.007641v1
120/10/1779    most recent
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Related articles in JCS
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 arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Cai, L.
Right arrow Articles by Bear, J. E.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cai, L.
Right arrow Articles by Bear, J. E.

Research Article

F-actin binding is essential for coronin 1B function in vivo

Liang Cai1, Alexander M. Makhov2 and James E. Bear1,*

1 Lineberger Comprehensive Cancer Center and Department of Cell & Developmental Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7295, USA
2 Department of Microbiology & Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, 27599-7295, USA

* Author for correspondence (e-mail: jbear{at}email.unc.edu)

Accepted 2 April 2007

Coronins are conserved F-actin binding proteins that have been implicated in a variety of processes including fibroblast migration, phagocytosis, and chemotaxis. Recent data from our lab indicate that coronin 1B coordinates Arp2/3-dependent actin filament nucleation and cofilin-mediated filament turnover at the leading edge of migrating fibroblasts. Analysis of coronin function has been hampered by the lack of a clear understanding of how coronin interacts with F-actin. Here, we identify a surface-exposed conserved arginine residue at position 30 (R30), which is crucial for coronin 1B binding to F-actin both in vitro and in vivo. Using actin co-sedimentation, we demonstrate that coronin 1B binds with high affinity to ATP/ADP-Pi–F-actin (170 nM) and with 47-fold lower affinity to ADP–F-actin (8 µM). In contrast to a previous study, we find no evidence for enhanced cofilin binding to F-actin in the presence of either coronin 1B or coronin 1A. Instead, we find that coronin 1B protects actin filaments from cofilin-induced depolymerization. Consistent with an important role for interactions between coronin 1B and F-actin in vivo, an R30D coronin mutant that does not bind F-actin localizes inefficiently to the leading edge. Furthermore, our analysis indicates that F-actin binding is absolutely required for coronin 1B to exert its effects on whole-cell motility and lamellipodial dynamics.

Key words: Coronin, Actin, Cofilin, Arp2/3, FRAP


Related articles in JCS:

Rivalry at the leading edge

JCS 2007 120: 1004. [Full Text]  



This article has been cited by other articles:


Home page
 J. Cell Biol.Home page
H. Y. Kueh, G. T. Charras, T. J. Mitchison, and W. M. Brieher
Actin disassembly by cofilin, coronin, and Aip1 occurs in bursts and is inhibited by barbed-end cappers
J. Cell Biol., July 28, 2008; 182(2): 341 - 353.
[Abstract] [Full Text] [PDF]


© The Company of Biologists Ltd 2007