BAI-1 Background Information Brain-specific angiogenesis inhibitors, including BAI-1, BAI-2, and BAI-3, are integral membrane proteins belonging to the G-protein coupled receptor 2 family. In addition to inhibiting angiogenesis in the brain, BAI proteins are also expressed in the heart, thymus, skeletal muscle, and a variety of cell lines. BAI-1 protein is specifically expressed in the brain and found to localize to the cytoplasm and membrane in neuronal cells of the cerebral cortex. Reduced expression of BAI-1 in some glioblastoma cell lines and cancer tissues implicates the functional role of BAI-1 as an inhibitor of angiogenesis. The exact mechanisms underlying BAI-1 anti-angiogenetic activity are still being investigated. BAI-1 may be involved in mediating the p53 signal in suppression of glioblastoma, as well as in cell adhesion and signal transduction. Additional research shows an inverse correlation with vascularization and BAI-1 expression in both colorectal carcinomas and pulmonary adenocarcinomas.
