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PubMed · 15548599

Actin-depolymerizing factor and cofilin-1 play overlapping roles in promoting rapid F-actin depolymerization in mammalian nonmuscle cells.

Pirta Hotulainen·Eija Paunola·Maria K Vartiainen·Pekka Lappalainen
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Abstract

Actin-depolymerizing factor (ADF)/cofilins are small actin-binding proteins found in all eukaryotes. In vitro, ADF/cofilins promote actin dynamics by depolymerizing and severing actin filaments. However, whether ADF/cofilins contribute to actin dynamics in cells by disassembling "old" actin filaments or by promoting actin filament assembly through their severing activity is a matter of controversy. Analysis of mammalian ADF/cofilins is further complicated by the presence of multiple isoforms, which may contribute to actin dynamics by different mechanisms. We show that two isoforms, ADF and cofilin-1, are expressed in mouse NIH 3T3, B16F1, and Neuro 2A cells. Depleting cofilin-1 and/or ADF by siRNA leads to an accumulation of F-actin and to an increase in cell size. Cofilin-1 and ADF seem to play overlapping roles in cells, because the knockdown phenotype of either protein could be rescued by overexpression of the other one. Cofilin-1 and ADF knockdown cells also had defects in cell motility and cytokinesis, and these defects were most pronounced when both ADF and cofilin-1 were depleted. Fluorescence recovery after photobleaching analysis and studies with an actin monomer-sequestering drug, latrunculin-A, demonstrated that these phenotypes arose from diminished actin filament depolymerization rates. These data suggest that mammalian ADF and cofilin-1 promote cytoskeletal dynamics by depolymerizing actin filaments and that this activity is critical for several processes such as cytokinesis and cell motility.

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ActinsAnimalsBlotting, WesternBridged Bicyclo Compounds, HeterocyclicCell Line, TumorCell MovementCell SizeCofilin 1CytokinesisDestrinFibroblastsFibronectinsFluorescein-5-isothiocyanateFluorescence Recovery After PhotobleachingFluorescent Antibody TechniqueFluorescent DyesGene SilencingIndolesKineticsMelanoma, ExperimentalMiceMicrofilament ProteinsMicroscopy, VideoNIH 3T3 CellsProtein IsoformsRNA, Small InterferingStress FibersThiazolesThiazolidinesComparative StudyJournal ArticleResearch Support, Non-U.S. Gov't

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Pirta Hotulainen, Eija Paunola, Maria K Vartiainen, Pekka Lappalainen. 2004-11-17. Actin-depolymerizing factor and cofilin-1 play overlapping roles in promoting rapid F-actin depolymerization in mammalian nonmuscle cells.. https://doi.org/10.1091/mbc.e04-07-0555

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