Function: 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. Ref.11
Catalytic activity: ATP + [receptor-protein] = ADP + [receptor-protein] phosphate.
Cofactor: Magnesium or manganese
By similarity.
Subunit structure: Homodimer. Heterohexamer; TGFB1, TGFB2 and TGFB3 homodimeric ligands assemble a functional receptor composed of two TGFBR1 and TGFBR2 heterodimers to form a ligand-receptor heterohexamer. The respective affinity of TGFRB1 and TGFRB2 for the ligands may modulate the kinetics of assembly of the receptor and may explain the different
biological activities of TGFB1, TGFB2 and TGFB3. Interacts with DAXX. Interacts with TCTEX1D4. Interacts with ZFYVE9; ZFYVE9 recruits SMAD2 and SMAD3 to the TGF-beta receptor. Interacts with and is activated by SCUBE3; this interaction does not affect TGFB1-binding to TGFBR2. Interacts with VPS39; this interaction is independent of the receptor kinase activity and of the presence of TGF-beta. Ref.12 Ref.13 Ref.14 Ref.15 Ref.16 Ref.19
Subcellular location: Cell membrane; Single-pass type I membrane protein Ref.1.
Post-translational modification: Phosphorylated on a Ser/Thr residue in the cytoplasmic domain.
Involvement in disease: Hereditary non-polyposis colorectal cancer 6 (HNPCC6) [MIM:614331]: An autosomal dominant disease associated with marked increase in cancer susceptibility. It is characterized by a familial predisposition to early-onset colorectal carcinoma (CRC) and extra-colonic tumors 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. Clinically, HNPCC is often divided into two subgroups. Type I is characterized by hereditary predisposition to colorectal cancer, a young age of onset, and carcinoma observed in the proximal colon. Type II is characterized by 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.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.25Esophageal cancer (ESCR) [MIM:133239]: A malignancy of the esophagus. The most common types are esophageal squamous cell carcinoma and adenocarcinoma. Cancer of the esophagus remains a devastating disease because it is usually not detected until it has progressed to an advanced incurable stage.Note: The disease is caused by mutations affecting the gene represented in this entry.Loeys-Dietz syndrome 1B (LDS1B) [MIM:610168]: 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.Note: The disease is caused by mutations affecting the gene represented in this entry. Ref.31 Ref.32 Ref.36 Ref.37 Ref.38 Ref.39Loeys-Dietz syndrome 2B (LDS2B) [MIM:610380]: An aortic aneurysm syndrome with widespread systemic involvement. Physical findings include diffuse arterial aneurysms and dissections, prominent joint laxity, easy bruising, wide and atrophic scars, velvety and translucent skin with easily visible veins, spontaneous rupture of the spleen or bowel, and catastrophic complications of pregnancy, including rupture of the gravid uterus and the arteries, either during pregnancy or in the immediate postpartum period. Loeys-Dietz syndrome type 2 is characterized by the absence of craniofacial abnormalities with the exception of bifid uvula that can be present in some patients.Note: The disease is caused by mutations affecting the gene represented in this entry. 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 (Ref.30), they have been considered as LDS2B by the OMIM resource. Ref.29 Ref.30 Ref.35
Sequence similarities: Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. TGFB receptor subfamily.Contains 1 protein kinase domain.
