The mode of subunit addition regulates the processive elongation of actin filaments by formin.

ABSTRACT: Formins play crucial roles in actin polymerization by nucleating filaments and regulating their elongation. Formins bind the barbed ends of filaments via their dimeric FH2 domains, which step processively onto incoming actin subunits during elongation. Actin monomers can bind formin-bound barbed ends directly or undergo diffusion-mediated delivery through interactions with formin FH1 domains and profilin. Despite its fundamental importance, a clear mechanism governing processive FH2 stepping has remained elusive. In this study, we systematically characterized the polymerization behavior of the Saccharomyces cerevisiae formin Bni1p using in vitro reconstitution assays and stochastic simulations. We found that Bni1p assembles populations of filaments with lengths that depend nonlinearly on t

SUBMITTER: Mahanta B 

PROVIDER: S-EPMC11773026 | biostudies-literature | 2025 Jan

REPOSITORIES: biostudies-literature