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. 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 SCAR2/DIS3 (WAVE complex). Expressed at low levels in all tissues with a relatively highest expression in inflorescences. Belongs to the ARPC3 family.