8elu
From Proteopedia
HRAS R97G Crystal form 1
Structural highlights
DiseaseRASH_HUMAN Defects in HRAS are the cause of faciocutaneoskeletal syndrome (FCSS) [MIM:218040. A rare condition characterized by prenatally increased growth, postnatal growth deficiency, mental retardation, distinctive facial appearance, cardiovascular abnormalities (typically pulmonic stenosis, hypertrophic cardiomyopathy and/or atrial tachycardia), tumor predisposition, skin and musculoskeletal abnormalities.[1] [2] [3] [4] [5] [6] [7] Defects in HRAS are the cause of congenital myopathy with excess of muscle spindles (CMEMS) [MIM:218040. CMEMS is a variant of Costello syndrome.[8] Defects in HRAS may be a cause of susceptibility to Hurthle cell thyroid carcinoma (HCTC) [MIM:607464. Hurthle cell thyroid carcinoma accounts for approximately 3% of all thyroid cancers. Although they are classified as variants of follicular neoplasms, they are more often multifocal and somewhat more aggressive and are less likely to take up iodine than are other follicular neoplasms. Note=Mutations which change positions 12, 13 or 61 activate the potential of HRAS to transform cultured cells and are implicated in a variety of human tumors. Defects in HRAS are a cause of susceptibility to bladder cancer (BLC) [MIM:109800. A malignancy originating in tissues of the urinary bladder. It often presents with multiple tumors appearing at different times and at different sites in the bladder. Most bladder cancers are transitional cell carcinomas. They begin in cells that normally make up the inner lining of the bladder. Other types of bladder cancer include squamous cell carcinoma (cancer that begins in thin, flat cells) and adenocarcinoma (cancer that begins in cells that make and release mucus and other fluids). Bladder cancer is a complex disorder with both genetic and environmental influences. Note=Defects in HRAS are the cause of oral squamous cell carcinoma (OSCC).[9] Defects in HRAS are the cause of Schimmelpenning-Feuerstein-Mims syndrome (SFM) [MIM:163200. A disease characterized by sebaceous nevi, often on the face, associated with variable ipsilateral abnormalities of the central nervous system, ocular anomalies, and skeletal defects. Many oral manifestations have been reported, not only including hypoplastic and malformed teeth, and mucosal papillomatosis, but also ankyloglossia, hemihyperplastic tongue, intraoral nevus, giant cell granuloma, ameloblastoma, bone cysts, follicular cysts, oligodontia, and odontodysplasia. Sebaceous nevi follow the lines of Blaschko and these can continue as linear intraoral lesions, as in mucosal papillomatosis.[10] FunctionRASH_HUMAN Ras proteins bind GDP/GTP and possess intrinsic GTPase activity.[11] [12] [13] Publication Abstract from PubMedRAS GTPases are proto-oncoproteins that regulate cell growth, proliferation, and differentiation in response to extracellular signals. The signaling functions of RAS, and other small GTPases, are dependent on their ability to cycle between GDP-bound and GTP-bound states. Structural analyses suggest that GTP hydrolysis catalyzed by HRAS can be regulated by an allosteric site located between helices 3, 4 and loop 7. Here we explore the relationship between intrinsic GTP hydrolysis on HRAS and the position of helix 3 and loop 7 through manipulation of the allosteric site, showing that the two sites are functionally connected. We generated several hydrophobic mutations in the allosteric site of HRAS to promote shifts in helix 3 relative to helix 4. By combining crystallography and enzymology to study these mutants, we show that closure of the allosteric site correlates with increased hydrolysis of GTP on HRAS in solution. Interestingly, binding to the RAS binding domain of RAF kinase (RAF-RBD) inhibits GTP hydrolysis in the mutants. This behavior may be representative of a cluster of mutations found in human tumors, which potentially cooperate with RAF complex formation to stabilize the GTP-bound state of RAS. This article is protected by copyright. All rights reserved. Allosteric site variants affect GTP hydrolysis on Ras.,Johnson CW, Fetics SK, Davis KP, Rodrigues JA, Mattos C Protein Sci. 2023 Aug 24:e4767. doi: 10.1002/pro.4767. PMID:37615343[14] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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