GTPase HRas (HRAS) (HRAS)

GTPase HRas, also known as Harvey rat sarcoma virus oncogene homolog, is a small G protein that functions as a critical molecular switch in cellular signal transduction (UniProt P01112). It belongs to the Ras superfamily of GTPases and cycles between an active GTP-bound state and an inactive GDP-bound state to regulate pathways such as MAPK/ERK and PI3K/Akt (PubMed: 22589270). These pathways are essential for controlling cell growth, differentiation, and survival. Mutations in the HRAS gene, particularly at codons 12, 13, and 61, result in a protein that is constitutively active, driving uncontrolled cellular proliferation and oncogenesis (PubMed: 25135305). HRAS mutations are prominently associated with specific malignancies, including head and neck squamous cell carcinoma, bladder cancer, and follicular thyroid cancer. Additionally, germline mutations in HRAS are the cause of Costello syndrome, a rare multisystem developmental disorder (PubMed: 16170316). From a therapeutic perspective, HRAS is a significant target because it is uniquely dependent on farnesylation for its membrane attachment and biological activity. This has led to the development of farnesyltransferase inhibitors, such as tipifarnib, which aim to disrupt HRAS localization and signaling in mutation-positive tumors (ClinicalTrials.gov: NCT02383927).

Other names

Harvey rat sarcoma virus oncogene homologHRAS1RASH1p21rasTransforming protein p21H-Ras

Farnesyltransferase inhibition to prevent membrane localization; competitive inhibition of GTP binding; disruption of effector protein interactions.