Phalloidin and DNase I-bound F-actin pointed end structures reveal principles of filament stabilization and disassembly.

ABSTRACT: Actin filament turnover involves subunits binding to and dissociating from the filament ends, with the pointed end being the primary site of filament disassembly. Several molecules modulate filament turnover, but the underlying mechanisms remain incompletely understood. Here, we present three cryo-EM structures of the F-actin pointed end in the presence and absence of phalloidin or DNase I. The two terminal subunits at the undecorated pointed end adopt a twisted conformation. Phalloidin can still bind and bridge these subunits, inducing a conformational shift to a flattened, F-actin-like state. This explains how phalloidin prevents depolymerization at the pointed end. Interestingly, two DNase I molecules simultaneously bind to the phalloidin-stabilized pointed end. In the absence of phallo

SUBMITTER: Boiero Sanders M 

PROVIDER: S-EPMC11390976 | biostudies-literature | 2024 Sep

REPOSITORIES: biostudies-literature