Functions as component of the Arp2/3 complex which is involved in regulation of actin polymerization and together with an activating nucleation-promoting factor (NPF) mediates the formation of branched actin networks. Component of the Arp2/3 complex composed of ARP2, ARP3, ARC40/p41-ARC, ARC35/p34-ARC, ARC18/p21-ARC, ARC19/p20-ARC and ARC16/p16-ARC. Present with 3060 molecules/cell in log phase SD medium. Belongs to the ARPC5 family.