The protein interactions of the BCL-2 family regulate programmed cell death or apoptosis, and therebymaintain the critical balance between cellular life and death. Pro-apoptotic BAX is a critical executioner proteinthat lies dormant in the cytosol until triggered by cellular stress to inflict irreversible damage on themitochondria. Because of its role as a gatekeeper of cell death, pharmacologic modulation of BAX has thepotential to alternatively block or reactivate cell death in diseases of deregulated apoptosis. BAX activation isbelieved to be a highly regulated, multi-step process involving an interaction-triggered conformational change,mitochondrial translocation, and homo-oligomerization to form a lethal pore within the outer mitochondrialmembrane. Using Stabilized Alpha-Helix of BCL-2 domains (SAHBs) that directly initiate BAX-mediatedmitochondrial apoptosis, we recently identified by NMR analysis a novel BAX interaction site that triggers itsactivation. Having tackled the initial step of BAX activation, I now propose to determine the elusive molecularmechanism of BAX auto-activation that leads to homo-oligomerization, so that this critical control point of theapoptotic pathway can be exploited therapeutically to inhibit cell death in hematologic disease. Specifically, Iaim to (1) synthesize structurally-reinforced alpha-helices corresponding to the BH3 death domain of BAX toidentify and characterize its interaction(s) with pro-apoptotic BAX, (2) determine the solution structures of theBAX SAHB-BAX complex and an intermediate BAX conformer, and (3) investigate the mechanism of BAXpropagation and the impact of its pharmacologic inhibition in hematologic cells. By operating at the interface ofchemistry, biology, and hematology, I hope to contribute new insight into our understanding of the BAX auto-activation pathway, revealing new sites of BCL-2 family protein interaction and determining how they can bepharmacologically reprogrammed for the betterment of hematology patients. The multidisciplinary scope of this proposal will require advanced training and expertise. With thementorship of Dr. Loren D. Walensky and Dr. Alan D'Andrea, I will acquire new skills and knowledge inchemical biology, apoptosis biology, and hematology, in addition to preparing for the transition toindependence through training in grantsmanship, laboratory management, the job application process, andother junior faculty survival skills. The proposed training and career development program within theDepartment of Pediatric Oncology at the Dana-Farber Cancer Institute and Harvard Medical School offersstate-of-the-art resources, world class faculty advisors and collaborators, and an outstanding environment tofacilitate a successful transition to academic independence. My career goal is to become an independentlyfunded principal investigator with a tenure-track position at a major academic research center. I am committedto a scientific career focused on the structure and function of protein interactions that regulate cell death, withdirect application to the development of novel pharmacologic strategies to treat hematologic disease.
Programmed cell death or apoptosis regulates the critical balance between cellular life and death and, when deregulated, contributes to the pathogenesis of a wide variety of hematologic diseases characterized by too many or too few blood cells. BCL-2 family proteins regulate apoptosis and analysis of their structure and function promises to elucidate opportunities for modulating apoptosis for therapeutic benefit. Using a combination of novel chemical tools, structural biology analyses, and hematologic cell experimentation, I aim to dissect and inhibit the activation mechanism of a critical executioner protein called BAX in order to protect hematologic cells from premature or unwanted cell death.
| Garner, Thomas P; Reyna, Denis E; Priyadarshi, Amit et al. (2016) An Autoinhibited Dimeric Form of BAX Regulates the BAX Activation Pathway. Mol Cell 64:431 |
| Uchime, Onyinyechukwu; Dai, Zhou; Biris, Nikolaos et al. (2016) Synthetic Antibodies Inhibit Bcl-2-associated X Protein (BAX) through Blockade of the N-terminal Activation Site. J Biol Chem 291:89-102 |
| Garner, Thomas P; Reyna, Denis E; Priyadarshi, Amit et al. (2016) An Autoinhibited Dimeric Form of BAX Regulates the BAX Activation Pathway. Mol Cell 63:485-97 |
| Barclay, Lauren A; Wales, Thomas E; Garner, Thomas P et al. (2015) Inhibition of Pro-apoptotic BAX by a noncanonical interaction mechanism. Mol Cell 57:873-886 |
| Cheng, Chunwei; Liu, Yan; Balasis, Maria E et al. (2014) Marinopyrrole derivatives with sulfide spacers as selective disruptors of Mcl-1 binding to pro-apoptotic protein Bim. Mar Drugs 12:4311-25 |
| Anguiano, Jaime; Garner, Thomas P; Mahalingam, Murugesan et al. (2013) Chemical modulation of chaperone-mediated autophagy by retinoic acid derivatives. Nat Chem Biol 9:374-82 |
| LaBelle, James L; Katz, Samuel G; Bird, Gregory H et al. (2012) A stapled BIM peptide overcomes apoptotic resistance in hematologic cancers. J Clin Invest 122:2018-31 |
| Whelan, Russell S; Konstantinidis, Klitos; Wei, An-Chi et al. (2012) Bax regulates primary necrosis through mitochondrial dynamics. Proc Natl Acad Sci U S A 109:6566-71 |
| Cohen, Nicole A; Stewart, Michelle L; Gavathiotis, Evripidis et al. (2012) A competitive stapled peptide screen identifies a selective small molecule that overcomes MCL-1-dependent leukemia cell survival. Chem Biol 19:1175-86 |
| Gavathiotis, Evripidis; Reyna, Denis E; Bellairs, Joseph A et al. (2012) Direct and selective small-molecule activation of proapoptotic BAX. Nat Chem Biol 8:639-45 |
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