Anti-Bif-1 from rabbit, purified by affinity chromatography

Endophilin-B1 (UniProt: Q9Y371; also known as Bax-interacting factor 1, Bif-1, SH3 domain-containing GRB2-like protein B1) is encoded by the SH3GLB1 (KIAA0491; CGI-61) gene (Gene ID: 51100) in human.Bif-1 is a member of the endophilin protein family that forms a complex with Beclin-1 through ultraviolet irradiation resistant-associated gene (UVRAG) and promotes the activation of the class III PI3 kinase, Vps34, in mammalian cells. It is highly expressed in heart, skeletal muscle, kidney, and placenta and is detected at lower levels in brain, colon, thymus, spleen, liver, small intestine, lung, and peripheral blood leukocytes. Loss of Bif-1 significantly suppresses PI3KC3 activation and the formation of autophagosome in both HeLa cells and mouse embryonic fibroblasts (MEFs). Bif-1 is reported to be involved in mitochondrial fission and coat protein complex I (COPI)-vesicle formation. Bif-1 contains a BAR domain at the N-terminal (aa 27-261) and a SH3 domain at the C-terminal (305-365), which is required for interaction with UVRAG. Bif-1 may be present as a homodimer or as a heterodimer with Endophilin-B2 (SH3GLB2). Bif-1 can be phosphorylated at Threonine 145 by Cdk5 and this phosphorylation is required for autophagy induction in starved neurons. Three isoforms of Bif-1 have been reported that are generated by alternative splicing. Isoform 1 acts as pro-apoptotic molecule in fibroblasts and is involved in caspase-independent apoptosis during nutrition starvation and in the regulation of autophagy. Isoform 2 has an anti-apoptotic role in neuronal cells and is involved in maintenance of mitochondrial morphology and promotes neuronal viability. (Ref.: Takahashi, Y et al (2009). Cell Death Differen. 16(7), 947-955).