MRAS Recombinant Rabbit mAb (S-4293-71)

MRAS (Muscle RAS Oncogene Homolog), also known as R-Ras3, is one of the members of the Ras small GTPase superfamily with the highest homology to the classical RAS oncoproteins (H-Ras, K-Ras, N-Ras). Its gene is located on chromosome 3q22.3 and is primarily highly expressed in tissues such as the brain and heart under normal physiological conditions. As a membrane-bound signal transduction protein, MRAS shares most of its regulatory factors (such as guanine nucleotide exchange factors like SOS1 and RasGRF) and effectors (such as RAF kinase and PI3K) with classical RAS. However, a breakthrough study published in 2025 revealed that MRAS is not a conventional "molecular switch"—it inherently lacks the capacity for nucleotide exchange between GDP and GTP, and even under GEF catalysis, it exists almost entirely in the inactive GDP-bound form, challenging the fundamental paradigm of Ras family protein function. The most unique feature of MRAS lies in its ability to form a ternary holoenzyme complex with SHOC2 and protein phosphatase 1 (PP1), which specifically dephosphorylates a critical 14-3-3 binding site on RAF kinase (such as S259 of CRAF), thereby relieving RAF autoinhibition and promoting synergistic activation of the downstream ERK signaling pathway. In addition, MRAS is involved in regulating cell polarity, migration, cytoskeletal remodeling, and integrin-mediated cell adhesion through the Rap1 pathway. Gain-of-function mutations in MRAS can cause Noonan syndrome (a developmental RASopathy), while genetic variants in this gene are also associated with traits such as coronary artery disease and platelet counts.