In neutrophils, RAC2 regulates NADPH oxidase NOX2 complex (Knaus et al. 1991, Kim et al. 2001) which consists of CYBB (NOX2), CYBA (p22phox), NCF1 (p47phox), NCF2 (p67phox) and NCF4 (p40phox). GTP-bound RAC2 binds to a conserved region of CYBB and tetratricopeptide repeats of NCF2 (Koga et al. 1999, Lapouge et al. 2000, Kao et al. 2008).