Functions as actin-binding 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. Seems to contact the mother actin filament (By similarity). Arp2/3 complex plays a critical role in the control of cell morphogenesis via the modulation of cell polarity development. Component of the Arp2/3 complex composed of ARP2, ARP3, ARPC1/p41-ARC, ARPC2/p34-ARC, ARPC3/p21-ARC, ARPC4/p20-ARC and ARPC5/p16-ARC. Interacts with ARPC4. Expressed at low levels in all tissues with a relatively highest expression in inflorescences. Distorted trichomes. Belongs to the ARPC2 family.