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

项目摘要/摘要 BCL-2家族蛋白是细胞凋亡的关键调节因子，细胞程序性死亡是正常细胞必不可少的一种形式 发育和组织动态平衡。放松对细胞凋亡机制的管制可以导致大量的人类 以细胞过多或过少为特征的疾病。抗细胞凋亡对细胞存活的病理强化作用 BCL-2家族蛋白与细胞死亡的Bax/BAK启动子结合并使其失活，可导致 人类癌症的发展、维持和化疗耐药。特别是，抗凋亡的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 通过与BCL-2家族中仅含BH3的成员的相互作用，从胞浆迁移到线粒体， 但bclw易位的生理触发机制和结构功能机制尚不清楚。这个 沃伦斯基实验室以前曾使用过装订的“BH3”多肽，它概括了自然结构和 这个关键的信号域的功能，以确定一个新的调节位点在促凋亡的Bax上介导 它的线粒体移位和由此产生的诱导细胞凋亡。具体地说，槽的BH3啮合 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 线粒体的靶向和插入。我推测bclw作为bax的抗凋亡同系物，可能 同样受制于其亚细胞分布的调节。阐明bclw易位 作用机制，我的目标是：(1)合成和表征稳定的bcl2结构域的α-螺旋(SAHBs) 模拟BH3螺旋以评估其与抗细胞凋亡的bcl-w的功能相互作用；(2)定位 与BH3触发的bclw易位相关的结合界面和诱导的构象变化；以及 (3)探讨应激诱导的bclw易位在肿瘤中的生理学意义。因此， 我的建议的首要目标是表征配体刺激的bcl的结构-功能机制。 W移位，并确定其在增强人类癌症细胞凋亡抵抗中的作用。我相信这一点 研究可能提供一种新的治疗策略，通过靶向破坏结合来解除癌症中bclw的武装。 驱动其线粒体易位的界面。我渴望参加严格的训练计划。 建议我在哈佛医学院和达纳-法伯癌症研究所攻读研究生学位 期待发展成为化学生物学界面上的独立和创新的研究人员， 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.