A nucleator arms race: cellular control of actin assembly.
For over a decade, the actin-related protein 2/3 (ARP2/3) complex, a handful of nucleation-promoting factors and formins were the only molecules known to directly nucleate actin filament formation de novo. However, the past several years have seen a surge in the discovery of mammalian proteins with roles in actin nucleation and dynamics. Newly recognized nucleation-promoting factors, such as WASP and SCAR homologue (WASH), WASP homologue associated with actin, membranes and microtubules (WHAMM), and junction-mediating regulatory protein (JMY), stimulate ARP2/3 activity at distinct cellular locations. Formin nucleators with additional biochemical and cellular activities have also been uncovered. Finally, the Spire, cordon-bleu and leiomodin nucleators have revealed new ways of overcoming the kinetic barriers to actin polymerization.
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA. campellone@berkeley.edu
Kenneth G
KG
Campellone
Matthew D
MD
Welch
D008841:Actin Cytoskeleton / Q000378:metabolism*; D051376:Actin-Related Protein 2-3 Complex / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000818:Animals; D006801:Humans; D009687:Nuclear Proteins / Q000502:physiology; D015534:Trans-Activators / Q000502:physiology; D051300:Wiskott-Aldrich Syndrome Protein Family / Q000502:physiology
D051376:Actin-Related Protein 2-3 Complex; D000199:Actins; C121977:JMY protein, human; D009687:Nuclear Proteins; D015534:Trans-Activators; D051300:Wiskott-Aldrich Syndrome Protein Family