Arp3b, or ARP3 actin-related protein 3 homolog B (yeast), is a human gene encoded by ACTR3B. It may also be known as: Actin-related protein 3B; ARP3-beta; Actin-like protein 3B; Actin-related protein ARP4; ARP3BETA. The encoded protein has an amino acid length of 418 and a mass of 47.6 kDa. Other isoforms may exist. Arp3b is a member of the Actin family, ARP3 subfamily. Homologs of this gene exist in other organisms, including: Mouse, Rat, Zebrafish, Chicken.