Instantaneous inactivation of cofilin reveals its function of F-actin disassembly in lamellipodia

• Type of Material: Article
• Authors: Eric A. Vitriol, Emory University; Ariel L. Wise, Emory University; Mathew E. Berginski, University of North Carolina at Chapel Hill; James R. Bamburg, Colorado State University; James Zheng, Emory University
• Language: English
• Date: 2013-07-15
• Publisher: American Society for Cell Biology
• Publication Version: Final Published Version
• Copyright Statement: © 2013 Vitriol et al.
• License: Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported
• Final Published Version (URL): http://www.molbiolcell.org/content/24/14/2238
• Title of Journal or Parent Work: Molecular Biology of the Cell
• ISSN: 1059-1524
• Volume: 24
• Issue: 14
• Start Page: 2238
• End Page: 2247
• Grant/Funding Information: This project is supported in part by research grants from the National Institutes of Health to J.Q.Z., an F32 fellowship from the National Institutes of Health to E.A.V., and National Institute of Neurological Disorders and Stroke Core Facilities grants to the Viral Vector Core (P30NS055077) and the Integrated Cellular Imaging Microscopy Core (P30NS055077) of Emory Neuroscience
• Research Categories: Biology, Molecular; Health Sciences, General; Biology, Cell

Abstract

Cofilin is a key regulator of the actin cytoskeleton. It can sever actin filaments, accelerate filament disassembly, act as a nucleation factor, recruit or antagonize other actin regulators, and control the pool of polymerization-competent actin monomers. In cells these actions have complex functional outputs. The timing and localization of cofilin activity are carefully regulated, and thus global, long-term perturbations may not be sufficient to probe its precise function. To better understand cofilin's spatiotemporal action in cells, we implemented chromophore-assisted laser inactivation (CALI) to instantly and specifically inactivate it. In addition to globally inhibiting actin turnover, CALI of cofilin generated several profound effects on the lamellipodia, including an increase of F-actin, a rearward expansion of the actin network, and a reduction in retrograde flow speed. These results support the hypothesis that the principal role of cofilin in lamellipodia at steady state is to break down F-actin, control filament turnover, and regulate the rate of retrograde flow.