ARPC3 and cystic fibrosis: At the same time, subunits of the Arp2/3 complex were differentially abundant from one another: Arp2/3 complex subunit 1A (ARPC1A) was less abundant in CF sweat while actin-related protein 2 (ACTR 2), Arp2/3 complex subunit 3 (ARPC3), and Arp2/3 complex subunit 4 (ARPC4) were more abundant.