Arp2/3 complex requires hydrolyzable ATP for nucleation of new actin filaments.

ABSTRACT: The Arp2/3 complex, a seven-subunit protein complex containing two actin-related proteins, Arp2 and Arp3, initiates formation of actin filament networks in response to intracellular signals. The molecular mechanism of filament nucleation, however, is not well understood. Arp2 and Arp3 are predicted to bind ATP via a highly conserved nucleotide-binding domain found in all members of the actin superfamily and to form a heterodimer than mimics a conventional actin dimer. We show here that adenosine nucleotides bind with micromolar affinity to both Arp2 and Arp3 and that hydrolyzable ATP is required for actin nucleation activity. Binding of N-WASP WA increases the affinity of both Arp2 and Arp3 for ATP but does not alter the stoichiometry of nucleotides bound in the presence of saturating conc

SUBMITTER: Dayel MJ 

PROVIDER: S-EPMC64951 | biostudies-literature | 2001 Dec

REPOSITORIES: biostudies-literature