Work

Cofilin Changes the Twist of F-Actin: Implications for Actin Filament Dynamics and Cellular Function

Year: 1997

Type: article

Abstract: Cofilin is an actin depolymerizing protein found widely distributed in animals and plants. We have used electron cryomicroscopy and helical reconstruction to identify its binding site on actin filaments. Cofilin binds filamentous (F)-actin cooperatively by bridging two longitudinally associated actin subunits. The binding site is centered axially at subdomain 2 of the lower actin subunit and radially at the cleft between subdomains 1 and 3 of the upper actin subunit. Our work has revealed a totally unexpected (and unique) property of cofilin, namely, its ability to change filament twist. As a consequence of this change in twist, filaments decorated with cofilin have much shorter 'actin crossovers' ( approximately 75% of those normally observed in F-actin structures). Although their binding sites are distinct, cofilin and phalloidin do not bind simultaneously to F-actin. This is the first demonstration of a protein that excludes another actin-binding molecule by changing filament twist. Alteration of F-actin structure by cofilin/ADF appears to be a novel mechanism through which the actin cytoskeleton may be regulated or remodeled.

Source: The Journal of Cell Biology

DOI: 10.1083/jcb.138.4.771

Authors: Amy McGough, Brian Pope, Wah Chiu, Alan Weeds

Institutions: MRC Laboratory of Molecular Biology, Baylor College of Medicine, Medical Research Council

Language: English

Topic: Cellular Mechanics and Interactions

Subfield: Cell Biology

Field: Biochemistry, Genetics and Molecular Biology

Domain: Life Sciences

Open Access status: green

Funder: National Center for Research Resources

Awards: G1497192632, G1688340195