ACVR2A/B Activin AB/B Activin AB/B:ACVR2A/B:ACVR1C Activin AB/B Binds Activin Receptor ACVR2A/B:ACVR1C As inferred from mouse, Activin binds the Activin receptor composed of a type II receptor (ACVR2A/B) and a type I receptor, in this case ACVR1C (ALK7). It is unclear if the type II receptor and the type I receptor are associated before binding Activin, Activin AB (INHBA:INHBB) and Activin B (INHBB:INHBB), but not Activin A (INHBA:INHBA) can bind and signal via an activin receptor containing the ACVR1C (ALK7) type I receptor. Authored: May, B, 2012-09-13 Edited: May, B, 2012-09-13 Reactome Database ID Release 432470483 Reactome, http://www.reactome.org ReactomeREACT_150244 Reviewed: Chen, Ye-Guang, 2012-11-14 has a Stoichiometric coefficient of 2