Cations Stiffen Actin Filaments by Adhering a Key Structural Element to Adjacent Subunits.

ABSTRACT: Ions regulate the assembly and mechanical properties of actin filaments. Recent work using structural bioinformatics and site-specific mutagenesis favors the existence of two discrete and specific divalent cation binding sites on actin filaments, positioned in the long axis between actin subunits. Cation binding at one site drives polymerization, while the other modulates filament stiffness and plays a role in filament severing by the regulatory protein, cofilin. Existing structural methods have not been able to resolve filament-associated cations, and so in this work we turn to molecular dynamics simulations to suggest a candidate binding pocket geometry for each site and to elucidate the mechanism by which occupancy of the "stiffness site" affects filament mechanical properties. Incorpor

SUBMITTER: Hocky GM 

PROVIDER: S-EPMC4959277 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature