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TRANSFORMING GROWTH FACTOR-BETA TYPE II RECEPTOR EXTRACELLULAR DOMAINTRANSFORMING GROWTH FACTOR-BETA TYPE II RECEPTOR EXTRACELLULAR DOMAIN
Structural highlights
DiseaseTGFR2_HUMAN Defects in TGFBR2 are the cause of hereditary non-polyposis colorectal cancer type 6 (HNPCC6) [MIM:614331. Mutations in more than one gene locus can be involved alone or in combination in the production of the HNPCC phenotype (also called Lynch syndrome). Most families with clinically recognized HNPCC have mutations in either MLH1 or MSH2 genes. HNPCC is an autosomal, dominantly inherited disease associated with marked increase in cancer susceptibility. It is characterized by a familial predisposition to early onset colorectal carcinoma (CRC) and extra-colonic cancers of the gastrointestinal, urological and female reproductive tracts. HNPCC is reported to be the most common form of inherited colorectal cancer in the Western world, and accounts for 15% of all colon cancers. Cancers in HNPCC originate within benign neoplastic polyps termed adenomas. Clinically, HNPCC is often divided into two subgroups. Type I: hereditary predisposition to colorectal cancer, a young age of onset, and carcinoma observed in the proximal colon. Type II: patients have an increased risk for cancers in certain tissues such as the uterus, ovary, breast, stomach, small intestine, skin, and larynx in addition to the colon. Diagnosis of classical HNPCC is based on the Amsterdam criteria: 3 or more relatives affected by colorectal cancer, one a first degree relative of the other two; 2 or more generation affected; 1 or more colorectal cancers presenting before 50 years of age; exclusion of hereditary polyposis syndromes. The term "suspected HNPCC" or "incomplete HNPCC" can be used to describe families who do not or only partially fulfill the Amsterdam criteria, but in whom a genetic basis for colon cancer is strongly suspected. HNPCC6 is a type of colorectal cancer complying with the clinical criteria of HNPCC, except that the onset of cancer was beyond 50 years of age in all cases.[1] Defects in TGFBR2 are a cause of esophageal cancer (ESCR) [MIM:133239. Defects in TGFBR2 are the cause of Loeys-Dietz syndrome type 1B (LDS1B) [MIM:610168. LDS1 is an aortic aneurysm syndrome with widespread systemic involvement. The disorder is characterized by arterial tortuosity and aneurysms, craniosynostosis, hypertelorism, and bifid uvula or cleft palate. Other findings include exotropy, micrognathia and retrognathia, structural brain abnormalities, intellectual deficit, congenital heart disease, translucent skin, joint hyperlaxity and aneurysm with dissection throughout the arterial tree.[2] [3] [4] [5] [6] [7] Defects in TGFBR2 are the cause of Loeys-Dietz syndrome type 2B (LDS2B) [MIM:610380. An aortic aneurysm syndrome with widespread systemic involvement. Physical findings include prominent joint laxity, easy bruising, wide and atrophic scars, velvety and translucent skin with easily visible veins, spontaneous rupture of the spleen or bowel, diffuse arterial aneurysms and dissections, and catastrophic complications of pregnancy, including rupture of the gravid uterus and the arteries, either during pregnancy or in the immediate postpartum period. LDS2 is characterized by the absence of craniofacial abnormalities with the exception of bifid uvula that can be present in some patients. Note=TGFBR2 mutations Cys-460 and His-460 have been reported to be associated with thoracic aortic aneurysms and dissection (TAAD). This phenotype, also known as thoracic aortic aneurysms type 3 (AAT3), is distinguised from LDS2B by having aneurysms restricted to thoracic aorta. As individuals carrying these mutations also exhibit descending aortic disease and aneurysms of other arteries (PubMed:16027248), they have been considered as LDS2B by the OMIM resource. FunctionTGFR2_HUMAN Transmembrane serine/threonine kinase forming with the TGF-beta type I serine/threonine kinase receptor, TGFBR1, the non-promiscuous receptor for the TGF-beta cytokines TGFB1, TGFB2 and TGFB3. Transduces the TGFB1, TGFB2 and TGFB3 signal from the cell surface to the cytoplasm and is thus regulating a plethora of physiological and pathological processes including cell cycle arrest in epithelial and hematopoietic cells, control of mesenchymal cell proliferation and differentiation, wound healing, extracellular matrix production, immunosuppression and carcinogenesis. The formation of the receptor complex composed of 2 TGFBR1 and 2 TGFBR2 molecules symmetrically bound to the cytokine dimer results in the phosphorylation and the activation of TGFRB1 by the constitutively active TGFBR2. Activated TGFBR1 phosphorylates SMAD2 which dissociates from the receptor and interacts with SMAD4. The SMAD2-SMAD4 complex is subsequently translocated to the nucleus where it modulates the transcription of the TGF-beta-regulated genes. This constitutes the canonical SMAD-dependent TGF-beta signaling cascade. Also involved in non-canonical, SMAD-independent TGF-beta signaling pathways.[8] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIsoforms of transforming growth factor beta (TGFbeta) are 25 kDa homodimeric polypeptides that signal by binding and bringing together two related, functionally distinct cell surface receptors designated as TbetaR1 and TbetaR2. Here, we report the solution structure of the 13.8 kDa extracellular domain of human TbetaR2 (ecTbetaR2) as calculated from N(N)-H(N), C(alpha)-H(alpha), and C(alpha)-C(O) residual dipolar coupling restraints in conjunction with NOE distance, dihedral angle, and scalar coupling restraints. Comparison of the free ecTbetaR2 solution structure with the TGFbeta3-bound ecTbetaR2 crystal structure reveals backbone conformations that superimpose with RMSDs of 1.0 A over the regions of regular secondary structure and 1.4 A overall. The differences in structure fall mainly in loop regions that are either poorly defined by the available NMR data or are involved in crystal contacts. The noted similarities between the NMR structure of the free form and the crystal structure of the TGFbeta-bound form are also consistent with the close correspondence, 0.16 A RMSD for regions of secondary structure and 0.51 A RMSD overall, for the crystal structure of free ecTbetaR2 as compared to the crystal structure of TGFbeta3-bound ecTbetaR2. Despite the apparent similarities between the free and the bound forms, there appears to be small but significant differences in structure involving the interfacial contact region of the receptor. Measurements of backbone (15)N relaxation times and interpretation of these by the model-free formalism with axial diffusional anisotropy further reveal significant ms to micros time scale motions centered about two of the conserved disulfide bonds and in several residues that comprise the TGFbeta binding surface. Together, these observations indicate that binding likely occurs through a mechanism with a small component of induced fit character, whereby flexibility within the receptor facilitates the transition to the TGFbeta-bound state. Solution structure and backbone dynamics of the TGFbeta type II receptor extracellular domain.,Deep S, Walker KP 3rd, Shu Z, Hinck AP Biochemistry. 2003 Sep 2;42(34):10126-39. PMID:12939140[9] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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