Cofilin produces newly polymerized actin filaments that are preferred for dendritic nucleation by the Arp2/3 complex

Ilia Ichetovkin, Wayne Grant, John S. Condeelis

Research output: Contribution to journalArticle

236 Citations (Scopus)

Abstract

One of the earliest events in the process of cell motility is the massive generation of free actin barbed ends, which elongate to form filaments adjacent to the plasma membrane at the tip of the leading edge. Both cofilin and Arp2/3 complex have been proposed to contribute to barbed end formation during cell motility. Attempts to assess the functions of cofilin and Arp2/3 complex in vivo indicate that both cofilin and Arp2/3 complex contribute to actin polymerization: cofilin by severing and Arp2/3 by nucleating and branching. In order to determine if the activities of cofilin and Arp2/3 complex interact, we employed a light microscope-based assay to visualize actin polymerization directly in the presence of both proteins. The results indicate that cofilin generates barbed ends to increase the mass of freshly polymerized F-actin but does not directly affect the activity of Arp2/3 complex. However, while ADP, ADP-Pi, and newly polymerized ATP-filaments are all capable of supporting Arp2/3-mediated branching, newly polymerized F-actin supports most of the Arp2/3-induced branch formation. The results suggest that, in vivo, cofilin contributes to barbed end formation byinducing the initial increase in the number of barbed ends leading to increased ATP-F-actin, which in turn supports higher levels of dendritic nucleation by active Arp2/3 complex.

Original languageEnglish (US)
Pages (from-to)79-84
Number of pages6
JournalCurrent Biology
Volume12
Issue number1
DOIs
StatePublished - Jan 8 2002

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Actin-Related Protein 2-3 Complex
Actin Depolymerizing Factors
microfilaments
Actin Cytoskeleton
actin
Actins
Nucleation
cell movement
polymerization
branching
Polymerization
Adenosine Diphosphate
Cell Movement
Adenosine Triphosphate
light microscopes
Cell membranes
plasma membrane
Assays
Microscopes
Cell Membrane

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)

Cite this

Cofilin produces newly polymerized actin filaments that are preferred for dendritic nucleation by the Arp2/3 complex. / Ichetovkin, Ilia; Grant, Wayne; Condeelis, John S.

In: Current Biology, Vol. 12, No. 1, 08.01.2002, p. 79-84.

Research output: Contribution to journalArticle

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