Activin A receptor type 1 (ACVR1) protein can bind activin in concert with activin receptor type 2 (ActRII) or activin receptor type-2B (ActRIIB). It participates in activin signaling. It is also capable of forming a complex with either the bone morphogenetic protein (BMP)-2/7-bound bone morphogenetic protein receptor type II (BMPR-II) or activin A receptor type 2A/2B (ACVR2A/ACVR2B). Somatic mutations of the ACVR1 gene are associated with primary ovary and colon cancer. It is considered a target gene to fibrodysplasia ossificans progressiva (FOP).