Gene Summary: The protein encoded by this gene forms a heteromeric complex with type II ALK5 receptors when bound to ALK5, transducing the ALK5 signal from the cell surface to the cytoplasm. The encoded protein is a serine/threonine protein kinase. Mutations in this gene have been associated with Loeys-Dietz aortic aneurysm syndrome (LDAS). Multiple transcript variants encoding different isoforms have been found for this gene. General information above from NCBI
Catalytic activity: ATP + [receptor-protein] = ADP + [receptor- protein] phosphate.
Cofactor: Magnesium or manganese (By similarity).
Enzyme regulation: Kept in an inactive conformation by FKBP1A preventing receptor activation in absence of ligand. CD109 is another inhibitor of the receptor.
Subunit structure: Homodimer; in the endoplasmic reticulum but also at the cell membrane. 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 TGBRB1 and TGFBR2 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 CD109; inhibits TGF-beta receptor activation in keratinocytes. Interacts with RBPMS. Interacts (unphosphorylated) with FKBP1A; prevents TGFBR1 phosphorylation by TGFBR2 and stabilizes it in the inactive conformation. Interacts with SMAD2, SMAD3 and ZFYVE9; ZFYVE9 recruits SMAD2 and SMAD3 to the TGF-beta receptor. Interacts with TRAF6 and MAP3K7; induces MAP3K7 activation by TRAF6. Interacts with PARD6A; involved in TGF-beta induced epithelial to mesenchymal transition. Interacts with SMAD7, NEDD4L, SMURF1 and SMURF2; SMAD7 recruits NEDD4L, SMURF1 and SMURF2 to the TGF-beta receptor. Interacts with USP15 and VPS39.
Domain: The SOCS box domain mediates the interaction with the Elongin BC complex, an adapter module in different E3 ubiquitin ligase complexes (By similarity).
Subcellular location: Cell membrane; Single-pass type I membrane protein. Cell junction, tight junction.
Tissue specificity: Found in all tissues examined, most abundant in placenta and least abundant in brain and heart.
Post-translational: Phosphorylated at basal levels in the absence of ligand. Activated upon phosphorylation by TGFBR2, mainly in the GS domain. Phosphorylation in the GS domain abbrogates FKBP1A-binding.
Ubiquitinated; undergoes ubiquitination catalyzed by several E3 ubiquitin ligases including SMURF1, SMURF2 and NEDD4L2. Results in the proteasomal and/or lysosomal degradation of the receptor thereby negatively regulating its activity. Deubiquitinated by USP15, leading to stabilization of the protein and enhanced TGF- beta signal.
Involvement in disease: Loeys-Dietz syndrome 1A (LDS1A) [MIM:609192]: 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.
Loeys-Dietz syndrome 2A (LDS2A) [MIM:608967]: 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. TGFBR1 mutation Gln-487 has been reported to be associated with thoracic aortic aneurysms and dissection (TAAD) (PubMed:16791849). This phenotype, also known as thoracic aortic aneurysms type 5 (AAT5), is distinguised from LDS2A by having aneurysms restricted to thoracic aorta. It is unclear, however, if this condition is fulfilled in individuals bearing Gln-487 mutation, that is why they are considered as LDS2A by the OMIM resource.
Multiple self-healing squamous epithelioma (MSSE) [MIM:132800]: A disorder characterized by multiple skin tumors that undergo spontaneous regression. Tumors appear most often on sun-exposed regions, are locally invasive, and undergo spontaneous resolution over a period of months leaving pitted scars. Note=The disease is caused by mutations affecting the gene represented in this entry.
Sequence similarity: Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. TGFB receptor subfamily.
Contains 1 GS domain.
Contains 1 protein kinase domain.
General information above from UniProt