Arp2/3 Complex

The Arp2/3 complex is originally identified in Acanthamoeba and consists of seven proteins (actin-related proteins; Arp2 and Arp3, and Arp2/3 complex subunits; ARPC1-5) that are conserved in all eukaryotes, with the exception of some algae, microsporidia and protists. The complex plays an essential role in a wide variety of cellular processes including lamellipodia-mediated cell migration, endocytosis and phagocytosis, by virtue of its ability to generate branched actin filament networks.

Activation of Arp2/3 requires interaction with actin nucleation-promoting factors (NPFs). Regulation of Arp2/3 activity is achieved by endogenous inhibitory proteins through direct binding to Arp2/3 and competition with NPFs or by binding to Arp2/3-induced actin filaments and disassembly of branched actin networks. Arp2/3 inhibition has recently garnered more attention as it has been associated with attenuation of cancer progression, neurotoxic effects during drug abuse, and pathogen invasion of host cells.