Activin Receptor Type IA on ligand binding, forms a receptor complex consisting of two type II and two type I transmembrane serine/threonine kinases. Type II receptors phosphorylate and activate type I receptors which autophosphorylate, then bind and activate SMAD transcriptional regulators. Activin receptor IA is highly conserved and is a receptor for BMP2 and BMP4. Activin type I receptors transduce signals for a variety of members of the Transforming growth factor beta superfamily of ligands. This family of cytokines and hormones inlude activin, Anti-müllerian hormone (AMH), bone morphogenetic proteins (BMPs), and Nodal. They are involved in a host of physiological processes including, growth, cell differentiation, homeostasis, osteogenesis, apoptosis and many other functions. There are three type I Activin receptors:ACVR1, ACVR1B, and ACVR1C Each bind to a specific type II receptor-ligand complex. Despite the large amount of processes that these ligands regulate, they all operate through essentially the same pathway: A ligand binds to a Type two receptor, which recruits and trans-phosphorylate a type I receptor. The type I receptor recruits a receptor regulated SMAD (R-SMAD) which it phosphorylates. The RSMAD then translocates to the nucleus where it functions as a transcription factor.
Alternate names: ACRV1A, ACVRLK2, ALK2, Activin receptor type IA, Activin receptor-like kinase 2, SKR1, Serine/threonine-protein kinase receptor R1, TGF-B superfamily receptor type I