title: Biophysics of actin filament severing by cofilin.
abstract: The continuous assembly and disassembly of actin filament networks is vital for cellular processes including division, growth, and motility. Network remodeling is facilitated by cofilins, a family of essential regulatory proteins that fragment actin filaments. Cofilin induces net structural changes in filaments that render them more compliant in bending and twisting. A model in which local stress accumulation at mechanical discontinuities, such as boundaries of bare and cofilin-decorated filament segments, accounts for the cofilin concentration dependence of severing, including maximal activity at sub-stoichiometric binding densities. Real-time imaging of cofilin-mediated filament severing supports the boundary-fracture model. The severing model predicts that fragmentation is promoted by factors modulating filament mechanics (e.g. tethering, cross-linking, or deformation), possibly explaining enhanced in vivo severing activities.
authors: Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
authors: W Austin
authors: WA
authors: Elam
authors: Hyeran
authors: H
authors: Kang
authors: Enrique M
authors: EM
authors: De la Cruz
mesh_terms: D008841:Actin Cytoskeleton / Q000737:chemistry* / Q000378:metabolism; D051339:Actin Depolymerizing Factors / Q000737:chemistry* / Q000378:metabolism; D000199:Actins / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D055592:Biophysical Phenomena; D006801:Humans; D007700:Kinetics; D008958:Models, Molecular; D011485:Protein Binding; D013816:Thermodynamics
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins
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