Instantaneous inactivation of cofilin reveals its function of F-actin disassembly in lamellipodia |
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| Authors: | Eric A Vitriol Ariel L Wise Mathew E Berginski James R Bamburg James Q Zheng |
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| Institution: | CEA Grenoble;aDepartments of Cell Biology and Neurology, Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA 30322;bDepartment of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;cDepartment of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, CO 80523 |
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| 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. |
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