Seems to be a coreceptor in inhibin signaling, but seems not to be a high-affinity inhibin receptor. Antagonizes activin A signaling in the presence or absence of inhibin B (By similarity). Necessary to mediate a specific antagonistic effect of inhibin B on activin-stimulated transcription.
Specificity
Natural and recombinant Human Immunoglobulin superfamily member 1
Interacts with INHA (By similarity). In PubMed:12385827 does not interact with INHA; standard receptor binding assay. Interacts with ACVR1B; the interaction appears to be ligand-dependent as it is diminished by inhibin B and activin A. Interacts with ACVR2A, ACVR2B, ACVRL1 and BMPR1B. Interacts with HECTD1.