Ras-GEF (IPR001895) is the catalytic domain of the Ras guanine nucleotide exchange factor. Guanine nucleotide exchange (or release) factor (GEF or GRF) (also known as guanine nucleotide dissociation stimulus (GDS)) induces the dissociation of GDP to permit a greater amount of GTP binding. GEF catalyzes the separation of GDP from inactive GTP-binding proteins, allowing GTP to bind and induce structural changes that support effectors in interacting .