Background
The Bcl-2 family consists of anti-apoptotic (or cell survival) genes, such as Bcl-2, Bcl-XL and pro-apoptotic (or cell death) genes including Bax and BAD. In addition to its anti-apoptotic effect, Bcl-2 also inhibits progression through the cell cycle. Functional interactions between family members as well as binding to other cellular proteins modulate their activities. Bcl-2 family members are important in normal tissue development, homeostasis, and disease states. Bcl-2 prevents cell death by forming heterodimers with Bax and Bad (1). Bax promotes cell death by forming homodimers, which can be blocked by forming heterodimers with Bcl-2 or BCL-XL. Recently, using yeast two-hybrid system Cuddeback et al (product citation 2) have identified a cDNA encoding a 365 amino acid protein, which interacts physically with Bax protein and influences cell life and death. Bif-1 contains a Src homology 3 (SH3) domain in the C-terminus. It does not contain any of the conserved Bcl-2 homology (BH) domains of the Bcl-2 family proteins. Human Bif-1 protein shares 96% and 42% identity at the amino acids level with mouse and C. elegans, respectively. Overexpression of Bif-1 in transfected cell lines promotes Bax conformational change, caspase activation, and apoptotic cell death following growth factor withdrawal. Bif-1 RNA is abundantly expressed in heart, skeletal muscle, kidney, and placenta.

Antigen
A full-length human Bif-1 recombinant protein was used as immunogen.

Application Notes
This antibody has not been tested in mouse models.  However, human and mouse Bif-1 are highly conserved and have 96% homology across the entire protein.

Genebank Info (Protein)
NP_057093

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Reference
1. Reed JC, J. Cell. Biol. 124: 1-6 (1994).

Product Citations
1. Loss of Bif-1 Suppresses Bax/Bak Conformational Change and Mitochondrial Apoptosis. Yoshinori Takahashi, Mariusz Karbowski, Hirohito Yamaguchi, Aslamuzzaman Kazi, Jie Wu, Saïd M. Sebti, Richard J. Youle, and Hong-Gang Wang. Mol. Cell. Biol., 25: 9369-9382 (2005).  (confirmed by siRNA experiment)
2. Endophilin B1 is required for the maintenance of mitochondrial morphology. Mariusz Karbowski, Seon-Yong Jeong, and Richard J. Youle. J. Cell Biol. 166(7): 1027-1039 (2004).
3. Molecular Cloning and Characterization of Bif-1. A NOVEL Src HOMOLOGY 3 DOMAIN-CONTAINING PROTEIN THAT ASSOCIATES WITH Bax. Sandy M. Cuddeback, Hirohito Yamaguchi, Kiyoshi Komatsu, Toshiyuki Miyashita, Masao Yamada, Chun Wu, Sujay Singh, and Hong-Gang Wang. J. Biol. Chem, 276: 20559-20565 (2001).
4. Endophilin B1/Bif-1 stimulates BAX activation independently from its capacity to produce large scale membrane morphologicla rearrangements.  Etexbarria A, O Terrones, H Yamaguchi, A Landajuela, O Landeta, B Antonsson, H Wang, G Bazanez. J Biol. Chem. 4200-4212 (2009). WB (rat liver mitochondria), Fig. 1A; 2A,B,C; 3D; 4B.
5. Bif-1 interacts with Beclin 1 through UVRAG and regulates autophage and tumorigenesis. Takahashi Y, D Coppola, N Matsushita, HD Cualing, M Sun, Y Satao, C Liang, JU Jung, JQ Cheng, JJ Mule, WJ Pledger, and HG Wang. Nature Cell Biol. 9:1142-1151. IP: Figs 5A (Mouse embryofibroblasts from Bif-1 WT and KO mice), 5D (293 cells transfected with GFP siRNA or UVRAG siRNA) and S5 (supplementary supporting data for Figs 5A and D).
Notes:
1. The Bif-1 antibody coprecipitated endogenous Beclin 1.
2. The Bif-1 antibody is mouse KO validated in Fig 5A.
6. Src directly phosphorylates Bif-1 and prevents its interaction with Bax and the initiation of anoikis. Yamaguchi H, N Woods, J Dorsey, Y Takahashi, N Gjertsen, T Yeatman, J Wu, H Wang. JBC 283: 19112-19118 (2008). IP (human 293T, A431, and NIH3T3 cell lines), Fig. 1C; 4D; 5C,D.