7lc2
Crystal Structure of KRAS4b-Q61R (GMPPNP-bound) in complex with the RAS-binding domain (RBD) of SIN1
Structural highlights
DiseaseRASK_HUMAN Defects in KRAS are a cause of acute myelogenous leukemia (AML) [MIM:601626. AML is a malignant disease in which hematopoietic precursors are arrested in an early stage of development.[1] Defects in KRAS are a cause of juvenile myelomonocytic leukemia (JMML) [MIM:607785. JMML is a pediatric myelodysplastic syndrome that constitutes approximately 30% of childhood cases of myelodysplastic syndrome (MDS) and 2% of leukemia. It is characterized by leukocytosis with tissue infiltration and in vitro hypersensitivity of myeloid progenitors to granulocyte-macrophage colony stimulating factor. Defects in KRAS are the cause of Noonan syndrome type 3 (NS3) [MIM:609942. Noonan syndrome (NS) [MIM:163950 is a disorder characterized by dysmorphic facial features, short stature, hypertelorism, cardiac anomalies, deafness, motor delay, and a bleeding diathesis. It is a genetically heterogeneous and relatively common syndrome, with an estimated incidence of 1 in 1000-2500 live births. Rarely, NS is associated with juvenile myelomonocytic leukemia (JMML). NS3 inheritance is autosomal dominant.[2] [3] [4] [5] [6] [7] Defects in KRAS are a cause of gastric cancer (GASC) [MIM:613659; also called gastric cancer intestinal or stomach cancer. Gastric cancer is a malignant disease which starts in the stomach, can spread to the esophagus or the small intestine, and can extend through the stomach wall to nearby lymph nodes and organs. It also can metastasize to other parts of the body. The term gastric cancer or gastric carcinoma refers to adenocarcinoma of the stomach that accounts for most of all gastric malignant tumors. Two main histologic types are recognized, diffuse type and intestinal type carcinomas. Diffuse tumors are poorly differentiated infiltrating lesions, resulting in thickening of the stomach. In contrast, intestinal tumors are usually exophytic, often ulcerating, and associated with intestinal metaplasia of the stomach, most often observed in sporadic disease.[8] [9] [10] Note=Defects in KRAS are a cause of pylocytic astrocytoma (PA). Pylocytic astrocytomas are neoplasms of the brain and spinal cord derived from glial cells which vary from histologically benign forms to highly anaplastic and malignant tumors.[11] Defects in KRAS are a cause of cardiofaciocutaneous syndrome (CFC syndrome) [MIM:115150; also known as cardio-facio-cutaneous syndrome. CFC syndrome is characterized by a distinctive facial appearance, heart defects and mental retardation. Heart defects include pulmonic stenosis, atrial septal defects and hypertrophic cardiomyopathy. Some affected individuals present with ectodermal abnormalities such as sparse, friable hair, hyperkeratotic skin lesions and a generalized ichthyosis-like condition. Typical facial features are similar to Noonan syndrome. They include high forehead with bitemporal constriction, hypoplastic supraorbital ridges, downslanting palpebral fissures, a depressed nasal bridge, and posteriorly angulated ears with prominent helices. The inheritance of CFC syndrome is autosomal dominant. Note=KRAS mutations are involved in cancer development. FunctionRASK_HUMAN Ras proteins bind GDP/GTP and possess intrinsic GTPase activity. Publication Abstract from PubMedRAS proteins are molecular switches that interact with effector proteins when bound to guanosine triphosphate, stimulating downstream signaling in response to multiple stimuli. Although several canonical downstream effectors have been extensively studied and tested as potential targets for RAS-driven cancers, many of these remain poorly characterized. In this study, we undertook a biochemical and structural approach to further study the role of Sin1 as a RAS effector. Sin1 interacted predominantly with KRAS isoform 4A in cells through an atypical RAS-binding domain that we have characterized by X-ray crystallography. Despite the essential role of Sin1 in the assembly and activity of mTORC2, we find that the interaction with RAS is not required for these functions. Cells and mice expressing a mutant of Sin1 that is unable to bind RAS are proficient for activation and assembly of mTORC2. Our results suggest that Sin1 is a bona fide RAS effector that regulates downstream signaling in an mTORC2-independent manner. RAS interaction with Sin1 is dispensable for mTORC2 assembly and activity.,Castel P, Dharmaiah S, Sale MJ, Messing S, Rizzuto G, Cuevas-Navarro A, Cheng A, Trnka MJ, Urisman A, Esposito D, Simanshu DK, McCormick F Proc Natl Acad Sci U S A. 2021 Aug 17;118(33):e2103261118. doi: , 10.1073/pnas.2103261118. PMID:34380736[12] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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