Dedicator of cytokinesis protein 8 (Dock8)

Guanine nucleotide exchange factor (GEF) which specifically activates small GTPase CDC42 by exchanging bound GDP for free GTP (PubMed:28028151, PubMed:22461490). During immune reactions, required for interstitial dendritic cell (DC) migration from locally activating CDC42 in the leading edge membrane of DC (PubMed:22461490, PubMed:25713392).

Required for CD4(+) T-cell migration in response to chemokine stimulation by promoting CDC42 activation at T cell leading edge membrane (PubMed:28028151). Is involved in NK cell cytotoxicity controlling polarization of microtubule-organizing center (MTOC), and potentially regulating CCDC88B-mediated lytic granule transport to MTOC during cell killing (By similarity).