Dissecting the Mitochondrial Translocation Mechanism of Anti-Apoptotic BCL-w

项目总结/摘要 BCL-2家族蛋白是细胞凋亡的关键调节因子，细胞凋亡是一种对正常发育至关重要的程序性细胞死亡形式。 发育和组织稳态。细胞凋亡机制的失调可导致许多人类细胞凋亡。 细胞过多或过少的疾病。抗凋亡药物对细胞存活的病理性强化 BCL-2家族蛋白结合并抑制细胞死亡的BAX/巴克启动子，可导致细胞死亡。 发展、维持和耐药性的研究。特别地，抗凋亡BCL-w具有 与多种人类癌症的进展和侵袭性有关。BCL-W被认为是 响应于与BCL-2家族的仅BH 3成员的相互作用而从细胞质迁移到线粒体， 但BCL-w易位的生理触发因素和结构-功能机制尚不清楚。的 Walensky实验室以前曾使用过钉合的“BH 3”肽，它概括了天然结构， 这个关键的信号结构域的功能，以确定一个新的调节位点的促凋亡BAX，介导 其线粒体易位和导致的凋亡诱导。具体地，凹槽的BH 3接合 由BAX的α-螺旋1和6并置形成的BAX诱导其C-末端螺旋的变构释放， 线粒体靶向和插入。我推测BCL-w作为BAX的抗凋亡同源物，可能 同样受到其亚细胞分布的调节。为了阐明BCL-w易位 本论文的主要目的是：（1）合成和表征BCL-2结构域稳定的α-螺旋结构域（SAHB）， 在BH 3螺旋之后建模以评估它们与抗凋亡BCL-w的功能相互作用;（2）定位BH 3螺旋的位置。 结合界面和诱导的与BH 3触发的BCL-w易位相关的构象变化;和 (3)研究癌症中应激诱导的BCL-w易位的生理意义。因此 我的建议的首要目标是描述配体刺激的BCL的结构-功能机制， W易位，并确定其对增强人类癌症中的凋亡抗性的贡献。我相信这 这项研究可以提供一种新的治疗策略，通过靶向破坏结合来解除癌症中的BCL-w， 驱动其线粒体易位的界面。我渴望参加严格的训练计划 我向哈佛医学院和丹娜-法伯癌症研究所提出了我的研究生学业， 期待着发展成为一个独立的和创新的研究者在化学生物学的接口， 细胞凋亡研究和癌症医学。

PROJECT SUMMARY/ABSTRACT BCL-2 family proteins are key regulators of apoptosis, a form of programmed cell death essential to normal development and tissue homeostasis. Deregulation of the apoptotic machinery can lead to a host of human diseases characterized by too many or too few cells. Pathologic enforcement of cell survival by anti-apoptotic BCL-2 family proteins, which bind to and inactivate the BAX/BAK initiators of cell death, can lead to the development, maintenance, and chemoresistance of human cancer. In particular, anti-apoptotic BCL-w has been linked to the progression and invasiveness of a broad range of human cancers. BCL-w is believed to migrate from cytosol to mitochondria in response to interaction with BH3-only members of the BCL-2 family, but the physiological triggers and structure-function mechanism of BCL-w translocation are unknown. The Walensky lab has previously employed stapled “BH3” peptides, which recapitulate the natural structure and function of this critical signaling domain, to identify a novel regulatory site on pro-apoptotic BAX that mediates its mitochondrial translocation and resultant induction of apoptosis. Specifically, BH3 engagement of a groove formed by the juxtaposition of α-helices 1 and 6 of BAX induces allosteric release of its C-terminal helix for mitochondrial targeting and insertion. I hypothesize that BCL-w, as an anti-apoptotic homologue of BAX, may likewise be subject to regulation of its subcellular distribution. To elucidate the BCL-w translocation mechanism, I aim to: (1) synthesize and characterize stabilized alpha-helix of BCL-2 domains (SAHBs) modeled after BH3 helices to assess their functional interactions with anti-apoptotic BCL-w; (2) locate the binding interface and induced conformational changes associated with BH3-triggered BCL-w translocation; and (3) investigate the physiologic implications of stress-induced BCL-w translocation in cancer. Thus, the overarching goal of my proposal is to characterize the structure-function mechanism for ligand-stimulated BCL- w translocation and determine its contribution to enforcing apoptotic resistance in human cancer. I believe this study could inform a novel therapeutic strategy to disarm BCL-w in cancer by targeted disruption of the binding interface that drives its mitochondrial translocation. I am eager to embark on the rigorous training program proposed for my graduate studies at Harvard Medical School and the Dana-Farber Cancer Institute and look forward to developing as an independent and innovative investigator at the interface of chemical biology, apoptosis research, and cancer medicine.