Insertional assembly of actin filament barbed ends in association with formins produces piconewton forces.

ABSTRACT: Formins are large multidomain proteins required for assembly of actin cables that contribute to the polarity and division of animal and fungal cells. Formin homology-1 (FH1) domains bind profilin, and highly conserved FH2 domains nucleate actin filaments. We characterized the effects of two formins, budding yeast Bni1p and fission yeast Cdc12p, on actin assembly. We used evanescent wave fluorescence microscopy to observe assembly of actin filaments (i) nucleated by soluble formin FH1FH2 domains and (ii) associated with formin FH1FH2 domains immobilized on microscope slides. Bni1p(FH1FH2)p and Cdc12p(FH1FH2)p nucleated new actin filaments or captured the barbed ends of preformed actin filaments that grew by insertion of subunits between the immobilized formin and the barbed end of the filam

SUBMITTER: Kovar DR 

PROVIDER: S-EPMC522035 | biostudies-literature | 2004 Oct

REPOSITORIES: biostudies-literature