High Quality Content by WIKIPEDIA articles! Dock2 (Dedicator of cytokinesis 2), also known as DOCK2, is a large (~180 kDa) protein involved in intracellular signalling networks. It is a member of the DOCK-A subfamily of the DOCK family of guanine nucleotide exchange factors (GEFs) which function as activators of small G proteins. Dock2 specifically activates isoforms of the small G protein Rac.