Ras homolog enriched in brain (Ras protein, GTP-bound state) (RAS (GTP-bound))

The GTP-bound Ras protein is the **active form** of Ras, a small GTPase acting as a molecular switch in intracellular signaling. When bound to GTP, **Ras undergoes conformational changes in the switch I and II regions, enabling it to interact with downstream effector proteins (such as Raf kinase, PI3K, and Ral-GDS), thereby propagating proliferative and survival signals**[1][2][4][5][6]. The three main human isoforms—HRAS, KRAS, and NRAS—cycle between an inactive GDP-bound state and an active GTP-bound state; this cycle is regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs)[1][2][5][6]. Dysregulation or mutation (particularly leading to constitutively GTP-bound, active signaling) is a **major driver of oncogenesis in many cancers**[1][2][6]. Selective inhibition of mutant GTP-bound KRAS proteins is an area of intense drug development, with clinical inhibitors now approved for certain KRAS mutations.

Other names

Ras GTPase (active state)GTP-bound RASH-Ras (GTP-bound)K-Ras (GTP-bound)N-Ras (GTP-bound)Ras oncogene protein (active state)

Covalent inhibition of mutant GTP-bound KRAS (e.g., G12C) blocks downstream signaling Disruption of RAS-effector interface (investigational)