DOCK9 (Dedicator of Cytokinesis 9) is a gene that encodes a guanine nucleotide exchange factor (GEF) protein. GEFs are key regulators that activate Rho family GTPases, which control essential cellular processes such as cytoskeletal organization, cell shape, and migration. DOCK9 plays a vital role in affecting cell morphology, adhesion, and movement, making it important in developmental biology and cancer progression.