BAI1, a p53-target gene, encodes brain-specific angiogenesis inhibitor, a seven-span transmembrane protein and is thought to be a member of the secretin receptor family. Brain-specific angiogenesis proteins BAI2 and BAI3 are similar to BAI1 in structure, have similar tissue specificities and may also play a role in angiogenesis.[6] The BAI3 receptor has also been found to regulate dendrite morphogenesis, arborization growth and branching in cultured neurons.[7]
The adhesion GPCR BaI3 is an orphan receptor that has a long N-terminus consisting of one cub domain, five BaI Thrombospondin type 1 repeats, and one hormone binding domain.[8] BaI3 is expressed in neural tissues of the central nervous system. BaI3 has been shown to have a high affinity for C1q proteins. C1q added to hippocampal neurons expressing BaI3 resulted in a decrease in the number of synapses.
Bjarnadóttir TK, Fredriksson R, Höglund PJ, Gloriam DE, Lagerström MC, Schiöth HB (July 2004). "The human and mouse repertoire of the adhesion family of G-protein-coupled receptors". Genomics. 84 (1): 23–33. doi:10.1016/j.ygeno.2003.12.004. PMID15203201.