The function of ACVRL1 (activin A receptor like type 1, ENSG00000139567) is as follows. Type I receptor for TGF-beta family ligands BMP9/GDF2 and BMP10 and important regulator of normal blood vessel development. 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 as well. {ECO:0000269|PubMed:22718755, ECO:0000269|PubMed:22799562, ECO:0000269|PubMed:26176610}.