Serine/threonine-protein kinase receptor R3 (ACVRL1)

Type I receptor for TGF-beta family ligands BMP9/GDF2 and BMP10 and important regulator of normal blood vessel growth. 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. May bind activin also.