extracellular domain (ECD) found in activin receptor-like kinase 5 (ALK-5) and similar proteins
ALK-5 (EC 2.7.11.30, also called TGF-beta receptor type-1 (TGFR-1), or activin A receptor type II-like protein kinase of 53kD, or serine/threonine-protein kinase receptor R4 (SKR4), or TGF-beta type I receptor, or transforming growth factor-beta receptor type I (TGFBR1), or TGF-beta receptor type I (TbetaR-I)) is the transmembrane serine/threonine kinase forming with the TGF-beta type II serine/threonine kinase receptor, TGFBR2, the non-promiscuous receptor for the TGF-beta cytokines TGFB1, TGFB2, and TGFB3. It 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. This model corresponds to the extracellular domain (ECD) of ALK-5, which belongs to Ly-6 antigen/uPA receptor-like (LU) superfamily and exhibits a snake toxin-like fold (also known as three-finger toxin/3FTx fold or three-fingered protein/TFP domain fold).
Jiyao W et al.(2023). "The conserved domain database in 2023.",