Energetic requirements for processive elongation of actin filaments by FH1FH2-formins.

ABSTRACT: Formin-homology (FH) 2 domains from formin proteins associate processively with the barbed ends of actin filaments through many rounds of actin subunit addition before dissociating completely. Interaction of the actin monomer-binding protein profilin with the FH1 domain speeds processive barbed end elongation by FH2 domains. In this study, we examined the energetic requirements for fast processive elongation. In contrast to previous proposals, direct microscopic observations of single molecules of the formin Bni1p from Saccharomyces cerevisiae labeled with quantum dots showed that profilin is not required for formin-mediated processive elongation of growing barbed ends. ATP-actin subunits polymerized by Bni1p and profilin release the gamma-phosphate of ATP on average >2.5 min after becomin

SUBMITTER: Paul AS 

PROVIDER: S-EPMC2673319 | biostudies-literature | 2009 May

REPOSITORIES: biostudies-literature