ALK4 Transmembrane serine/threonine kinase activin type-1 receptor forming an activin receptor complex with activin receptor type-2 (ACVR2A or ACVR2B). Transduces the activin signal from the cell surface to the cytoplasm and is thus regulating a many physiological and pathological processes including neuronal differentiation and neuronal survival, hair follicle development and cycling, FSH production by the pituitary gland, wound healing, extracellular matrix production, immunosuppression and carcinogenesis. Activin is also thought to have a paracrine or autocrine role in follicular development in the ovary. Within the receptor complex, type-2 receptors (ACVR2A and/or ACVR2B) act as a primary activin receptors whereas the type-1 receptors like ACVR1B act as downstream transducers of activin signals. Activin binds to type-2 receptor at the plasma membrane and activates its serine-threonine kinase. The activated receptor type-2 then phosphorylates and activates the type-1 receptor such as ACVR1B. Once activated, the type-1 receptor binds and phosphorylates the SMAD proteins SMAD2 and SMAD3, on serine residues of the C-terminal tail. Soon after their association with the activin receptor and subsequent phosphorylation, SMAD2 and SMAD3 are released into the cytoplasm where they interact with the common partner SMAD4. This SMAD complex translocates into the nucleus where it mediates activin-induced transcription. Inhibitory SMAD7, which is recruited to ACVR1B through FKBP1A, can prevent the association of SMAD2 and SMAD3 with the activin receptor complex, thereby blocking the activin signal. Activin signal transduction is also antagonized by the binding to the receptor of inhibin-B via the IGSF1 inhibin coreceptor. ACVR1B also phosphorylates TDP2. Belongs to the protein kinase superfamily. TKL Ser/Thr protein kinase family. TGFB receptor subfamily. Expressed in many tissues, most strongly in kidney, pancreas, brain, lung, and liver. 3 alternatively spliced human isoforms have been reported. Note: This description may include information from UniProtKB.
Protein type: EC; Kinase, protein; Membrane protein, integral; Protein kinase, Ser/Thr (receptor); Protein kinase, TKL; STKR family; TKL group; Type1 subfamily
Chromosomal Location of Human Ortholog: 15 F1|15 56.48 cM
Cellular Component:  activin receptor complex; cell surface; cytosol; integral component of membrane; integral component of plasma membrane; membrane; plasma membrane; receptor complex
Molecular Function:  activin binding; activin receptor activity, type I; ATP binding; growth factor binding; inhibin binding; kinase activity; metal ion binding; nucleotide binding; protein binding; protein kinase activity; protein serine/threonine kinase activity; SMAD binding; transferase activity; transforming growth factor beta receptor activity, type I; transforming growth factor beta-activated receptor activity; transmembrane receptor protein serine/threonine kinase activity
Biological Process:  activin receptor signaling pathway; cell surface receptor signaling pathway; extrinsic apoptotic signaling pathway; G1/S transition of mitotic cell cycle; hair follicle development; in utero embryonic development; mesoderm development; negative regulation of cell growth; negative regulation of gene expression; nodal signaling pathway; pattern specification process; peptidyl-threonine phosphorylation; phosphorylation; positive regulation of activin receptor signaling pathway; positive regulation of erythrocyte differentiation; positive regulation of gene expression; positive regulation of pathway-restricted SMAD protein phosphorylation; positive regulation of transcription by RNA polymerase II; positive regulation of trophoblast cell migration; protein autophosphorylation; protein phosphorylation; regulation of signal transduction; regulation of transcription, DNA-templated; signal transduction; transforming growth factor beta receptor signaling pathway
Reference #:  Q61271 (UniProtKB)
Alt. Names/Synonyms: 6820432J04; activin A receptor, type 1B; Activin receptor type IB; Activin receptor type-1B; Activin receptor-like kinase 4; ACTR-IB; ActRIB; ACV1B; Acvr1b; Acvrlk4; ALK-4; Alk4; Serine/threonine-protein kinase receptor R2; SKR2
Gene Symbols: Acvr1b
Molecular weight: 56,700 Da
Basal Isoelectric point: 6.76  Predict pI for various phosphorylation states
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Protein Structure Not Found.

Cross-references to other databases:  STRING  |  Reactome  |  BioGPS  |  KinBase  |  Pfam  |  ENZYME  |  Phospho.ELM  |  NetworKIN  |  UniProtKB  |  Entrez-Gene  |  Ensembl Gene