Instantaneous Inactivation of Cofilin Reveals Its Function of F-actin Disassembly in Lamellipodia

Mol Biol Cell. 2013 Jul;24(14):2238-47. doi: 10.1091/mbc.E13-03-0156. Epub 2013 May 15.

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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Actin Cytoskeleton / metabolism*
  • Actin Cytoskeleton / radiation effects
  • Actin Cytoskeleton / ultrastructure
  • Actin Depolymerizing Factors / antagonists & inhibitors
  • Actin Depolymerizing Factors / genetics
  • Actin Depolymerizing Factors / metabolism*
  • Actins / agonists
  • Actins / genetics
  • Actins / metabolism*
  • Animals
  • Cell Line, Tumor
  • Gene Expression Regulation
  • Genes, Reporter
  • Green Fluorescent Proteins / genetics
  • Green Fluorescent Proteins / metabolism
  • Half-Life
  • Kinetics
  • Lasers
  • Mice
  • Neurons / cytology
  • Neurons / metabolism*
  • Neurons / radiation effects
  • Photosensitizing Agents / chemistry
  • Photosensitizing Agents / metabolism
  • Protein Stability
  • Pseudopodia / metabolism*
  • Pseudopodia / radiation effects
  • Pseudopodia / ultrastructure
  • Staining and Labeling / methods
  • Time Factors

Substances

  • Actin Depolymerizing Factors
  • Actins
  • Photosensitizing Agents
  • killer red protein, Anthomedusae
  • Green Fluorescent Proteins