title: Remodeling of actin filaments by ADF/cofilin proteins.
abstract: Cofilin/ADF proteins play key roles in the dynamics of actin, one of the most abundant and highly conserved eukaryotic proteins. We used cryoelectron microscopy to generate a 9-Å resolution three-dimensional reconstruction of cofilin-decorated actin filaments, the highest resolution achieved for a complex of F-actin with an actin-binding protein. We show that the cofilin-induced change in the filament twist is due to a unique conformation of the actin molecule unrelated to any previously observed state. The changes between the actin protomer in naked F-actin and in the actin-cofilin filament are greater than the conformational changes between G- and F-actin. Our results show the structural plasticity of actin, suggest that other actin-binding proteins may also induce large but different conformational changes, and show that F-actin cannot be described by a single molecular model.
authors.affiliation: Department of Biochemistry and Molecular Genetics, University of Virginia, Box 800733, Charlottesville, VA 22908-0733, USA. galkin@virginia.edu
authors.forename: Vitold E
authors.initials: VE
authors.lastname: Galkin
authors.forename: Albina
authors.initials: A
authors.lastname: Orlova
authors.forename: Dmitri S
authors.initials: DS
authors.lastname: Kudryashov
authors.forename: Alexander
authors.initials: A
authors.lastname: Solodukhin
authors.forename: Emil
authors.initials: E
authors.lastname: Reisler
authors.forename: Gunnar F
authors.initials: GF
authors.lastname: Schröder
authors.forename: Edward H
authors.initials: EH
authors.lastname: Egelman
mesh_terms: D051339:Actin Depolymerizing Factors / Q000737:chemistry*; D000199:Actins / Q000737:chemistry*; D051340:Cofilin 2 / Q000737:chemistry*; D020285:Cryoelectron Microscopy / Q000379:methods; D003599:Cytoskeleton / Q000737:chemistry*; D015723:Gene Library; D006801:Humans; D008854:Microscopy, Electron / Q000379:methods; D008958:Models, Molecular; D008968:Molecular Conformation; D018482:Muscle, Skeletal / Q000378:metabolism; D011108:Polymers / Q000737:chemistry*; D011487:Protein Conformation; D017433:Protein Structure, Secondary
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D051340:Cofilin 2; D011108:Polymers