The BCL-2 family pro-apoptotic proteins have tumor suppressive functions and are important for conferring chemosensitivity to anti-neoplastic drugs. In animal cells, various apoptotic stimuli activate expression of specific BH3-only proteins. These proteins induce apoptogenic conversion of BH123 proteins (BAX and BAK) that leads to cell death. The molecular mechanisms of how BH3-only proteins activate BH123 proteins are unknown. BIK, the founding member of the BH3-only family mediates its pro-apoptotic activity primarily through BAX in human epithelial cancer cells. We will investigate a major hypothesis that interaction of BIK with BCL-2 family anti-apoptotic members such as BCL-2 results in functional activation of BAX and specific sequences in BAX determine functional activation BAX.
Aim 1 will identify the BAX sequences that are important for BAX activation and function from a library of random and targeted mutants of Bax and by studying the effect of various Bax isoforms. Functionally altered Bax mutants will be studied to determine the effects on subcellular localization, membrane insertion, oligomerization and structural properties.
Aim 2 will investigate the specificity of various human BH3-only proteins for the human BH123 proteins BAX and BAK in normal human cells depleted for these proteins or in mouse double knockout cells reconstituted with the human proteins.
Aim 3 will investigate if the pro-apoptotic activity of BIK is linked to its ability to interact with BCL-2 family anti-apoptosis proteins and test a potential model for BAX activation through BIK interaction with BH1234 proteins.
Aim 4 will investigate the hypothesis that BIK-induced apoptosis is initiated at the endoplasmic reticulum and amplified in the mitochondria. Specifically, the potential role of BIK in disruption of intracellular calcium homeostasis and the involvement of the cysteine protease calpain in apoptosis signaling by BIK will be investigated. The proposed studies should illuminate the apoptotic pathway by which BIK activates the apoptotic machinery through BAX. The knowledge gained would be valuable in modulating the activity of BAX in cancer and in degenerative diseases.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Cancer Molecular Pathobiology Study Section (CAMP)
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Spalholz, Barbara A
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Saint Louis University
Schools of Medicine
Saint Louis
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Vijayalingam, S; Pillai, Sreeraj G; Rashmi, Ramachandran et al. (2010) Overexpression of BH3-Only Protein BNIP3 Leads to Enhanced Tumor Growth. Genes Cancer 1:964-71
Lomonosova, Elena; Ryerse, Jan; Chinnadurai, G (2009) BAX/BAK-independent mitoptosis during cell death induced by proteasome inhibition? Mol Cancer Res 7:1268-84
Chinnadurai, G; Vijayalingam, S; Rashmi, R (2008) BIK, the founding member of the BH3-only family proteins: mechanisms of cell death and role in cancer and pathogenic processes. Oncogene 27 Suppl 1:S20-9
Rashmi, R; Pillai, S G; Vijayalingam, S et al. (2008) BH3-only protein BIK induces caspase-independent cell death with autophagic features in Bcl-2 null cells. Oncogene 27:1366-75
Chinnadurai, G; Vijayalingam, S; Gibson, S B (2008) BNIP3 subfamily BH3-only proteins: mitochondrial stress sensors in normal and pathological functions. Oncogene 27 Suppl 1:S114-27
Lomonosova, E; Chinnadurai, G (2008) BH3-only proteins in apoptosis and beyond: an overview. Oncogene 27 Suppl 1:S2-19
Subramanian, T; Vijayalingam, S; Lomonosova, Elena et al. (2007) Evidence for involvement of BH3-only proapoptotic members in adenovirus-induced apoptosis. J Virol 81:10486-95
Subramanian, T; Chinnadurai, G (2003) Pro-apoptotic activity of transiently expressed BCL-2 occurs independent of BAX and BAK. J Cell Biochem 89:1102-14
Lomonosova, Elena; Subramanian, T; Chinnadurai, G (2002) Requirement of BAX for efficient adenovirus-induced apoptosis. J Virol 76:11283-90
Theodorakis, Paul; Lomonosova, Elena; Chinnadurai, G (2002) Critical requirement of BAX for manifestation of apoptosis induced by multiple stimuli in human epithelial cancer cells. Cancer Res 62:3373-6

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