Functions as a guanine nucleotide exchange factor (GEF), which activates Rac1 and Rac3 Rho small GTPases by exchanging bound GDP for free GTP. Does not have a GEF activity for CDC42. Required for STMN1 'Ser-15' phosphorylation during axon formation and consequently for neuronal polarization (By similarity). As part of the DISP complex, may regulate the association of septins with actin and thereby regulate the actin cytoskeleton (By similarity). Has a role in pigmentation (PubMed:19202056). Involved in the regulation of cortical neurogenesis through the control of radial glial cells (RGCs) proliferation versus differentiation; negatively regulates the basal-to-apical interkinetic nuclear migration of RGCs by antagonizing the microtubule growth-promoting function of TACC3 (PubMed:22842144). Component of the DOCK7-induced septin displacement/DISP complex, at least composed of DOCK7, LRCH3 and MYO6 (By similarity). Interacts with TSC1 (By similarity). Interacts with nucleotide-free RAC1 and RAC3 (By similarity). Interacts with TACC3. Interacts with CRY1. Interacts with NOD2 (By similarity). Enriched in the developing axons of hippocampal neurons. The DOCKER domain mediates GEF activity. Defects in Dock7 are responsible for the moonlight phenotype (mnlt). mnlt/mnlt mice display an overall lightened coat color and hypopigmentation of the belly and distal extremities, particularly the paws, tail tip, and genitalia. Belongs to the DOCK family. Extended N-terminus. Truncated N-terminus. Truncated N-terminus.