Brain-specific angiogenesis inhibitor 3 (ADGRB3) is a G-protein coupled receptor. Along with BAI3, there are two other brain-specific angiogenesis inhibitor genes, designated BAI1 and BAI2, which have similar tissue specificities and structures. BAI3 binds to C1ql proteins with high affinity, mediated by the globular C1q domains of the C1ql proteins, which act to regulate synapse formation and/or maintenance. BAI3 has also been shown to control myoblast fusion in developing vertebrate muscle. References: Proc Natl Acad Sci U S A. 2011 Feb 8; 108(6): 2534–2539.; PNAS March 11, 2014 111 (10) 3745-3750;