The long-term goal for this project is to elucidate the molecular mechanism for the regulation of programmed cell death. Understanding the mechanism is the key to the development of effective treatments for a wide variety of human diseases such as cancer as ischemia, in which apoptosis is either inhibited or accelerated. The fundamental question we will address is how Bcl-XL and Bax can have opposite functions (anti- and pro- cell death, respectively) yet display similar structures in solution.
The specific aims are to determine (1) the structural basis for tBid-activated oligomerization of pro-apoptotic Bax in the mitochondrial outer membrane;and (2) the structural basis for inhibition of tBid-activated Bax by Bcl-XL. To complete the project, we will study the interactions between tBid, Bax and/or Bcl-XL using site-specific cross-linking, chemical labeling and fluorescence techniques. We will also generate mutations in these proteins to elucidate the structure-function relationship. By completing this systematic and thorough investigation, we will generate useful structural information about the membrane-embedded protein complexes, which may facilitate rational design of chemical inhibitors to target either the anti- or the pro-cell death complex for therapeutic benefits.

Public Health Relevance

The project is to find ways to interfere with programmed cell death, and to treat cell death-related diseases such as cancer and stroke. The study will focus on the structure and interaction of cell death regulatory proteins that are potential drug targets.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Research Project (R01)
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Study Section
Cellular Signaling and Regulatory Systems Study Section (CSRS)
Program Officer
Chin, Jean
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University of Oklahoma Health Sciences Center
Schools of Medicine
Oklahoma City
United States
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Ding, Jingzhen; Mooers, Blaine H M; Zhang, Zhi et al. (2014) After embedding in membranes antiapoptotic Bcl-XL protein binds both Bcl-2 homology region 3 and helix 1 of proapoptotic Bax protein to inhibit apoptotic mitochondrial permeabilization. J Biol Chem 289:11873-96
Medina, Andria P; Lin, Jialing; Weigel, Paul H (2012) Hyaluronan synthase mediates dye translocation across liposomal membranes. BMC Biochem 13:2
Zhao, Lixia; He, Feng; Liu, Haiyang et al. (2012) Natural diterpenoid compound elevates expression of Bim protein, which interacts with antiapoptotic protein Bcl-2, converting it to proapoptotic Bax-like molecule. J Biol Chem 287:1054-65
Ko, Jae-Kyun; Choi, Kyoung-Han; Peng, Jun et al. (2011) Amphipathic tail-anchoring peptide and Bcl-2 homology domain-3 (BH3) peptides from Bcl-2 family proteins induce apoptosis through different mechanisms. J Biol Chem 286:9038-48
Ding, Jingzhen; Zhang, Zhi; Roberts, G Jane et al. (2010) Bcl-2 and Bax interact via the BH1-3 groove-BH3 motif interface and a novel interface involving the BH4 motif. J Biol Chem 285:28749-63
Leber, B; Lin, J; Andrews, D W (2010) Still embedded together binding to membranes regulates Bcl-2 protein interactions. Oncogene 29:5221-30
Zhang, Zhi; Zhu, Weijia; Lapolla, Suzanne M et al. (2010) Bax forms an oligomer via separate, yet interdependent, surfaces. J Biol Chem 285:17614-27
Peng, Jun; Lapolla, Suzanne M; Zhang, Zhi et al. (2009) The cytosolic domain of Bcl-2 forms small pores in model mitochondrial outer membrane after acidic pH-induced membrane association. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 26:130-7
Peng, Jun; Lapolla, Suzanne M; Zhang, Zhi et al. (2009) The Bax BH3 peptide H2-H3 promotes apoptosis by inhibiting Bcl-2's pore-forming and anti-Bax activities in the membrane. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 26:829-35
Peng, Jun; Lapolla, Suzanne M; Zhang, Zhi et al. (2009) The cytosolic domain of Bcl-2 oligomerizes to form pores in model mitochondrial outer membrane at acidic pH. Sheng Wu Yi Xue Gong Cheng Xue Za Zhi 26:631-7

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