GTPaasit
GTPases are a broad family of enzymes that bind guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP). In their GTP-bound state they are typically active and act as molecular switches that regulate a variety of cellular processes, while conversion to GDP-bound form often halts signaling or activity. Activation and inactivation are tightly controlled by regulatory proteins: guanine nucleotide exchange factors (GEFs) promote the exchange of GDP for GTP, GTPase-activating proteins (GAPs) accelerate GTP hydrolysis, and, for many small GTPases, guanine nucleotide dissociation inhibitors (GDIs) modulate localization and nucleotide exchange.
Most GTPases belong to the P-loop NTPase superfamily and share a conserved GTPase domain, with switch regions
Two major classes are recognized: small GTPases of the Ras superfamily (including Ras, Rho, Rab, Arf and
Dysregulation of GTPases is linked to diseases including cancer (notably Ras mutations) and developmental disorders. Therapeutic