Regulation and function of the pro-apoptotic Bcl-2 family member BOK

促凋亡 Bcl-2 家族成员 BOK 的调节和功能

• 批准号: 392470008
• 负责人: Dr. Halime Kalkavan
• 金额: --
• 依托单位: Department of Immunology
• 依托单位国家: 德国
• 项目类别: Research Fellowships
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2019-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/392470008?language=en
• 关键词: Regulation; function; pro; apoptotic; Bcl

Therapeutic strategies in cancer are directed towards inducing cell death. Understanding how cells activate or suppress pro-apoptoic signalling is therefore a key issue if effective anti-cancer therapies are to be developed. The BCL2 family of pro- and anti-apoptotic members plays a crucial role in the choice between cell survival and death by controlling the process of mitochondrial outer membrane permeabilization (MOMP). The three active effectors of MOMP are BAX, BAK and the Bcl-2-related ovarian killer (BOK). In stark contrast to BAX and BAK, BOK is not regulated by anti-apoptotic BCL2 family members (e.g., BCL-2, BCL-xL, BCL-W, MCL-1). In most cell lines examined to date the pro-apoptotic activity of the MOMP effector BOK is suppressed via ubiquitin-mediated degradation. Consequently in cells with “unstable“ BOK the protein is barely detectable. Stabilization of BOK in such cell lines via proteasome inhibition or overexpression of BOK leads to apoptotic cell death. These and other findings suggest that BOK is a constitutively active MOMP effector and that the apoptotic activity of BOK is inhibited by the actions of the cytosolic arm of the ER-associated degradation (ERAD) pathway.By contrast, we observed that several organs and cancer cell lines harbor constitutively “stabilized“ BOK protein, suggesting that BOK’s MOMP effector function is inactivated via an alternative mechanism to proteosomal degradation. Our preliminary data suggest, that certain cellular stresses (e.g., mitotic damage, ER-stress) can activate constitutively stabilized BOK, but how this occurs is unknown.The proposed project will therefore explore the effects of BOK on apoptosis in cells that maintain stabilized BOK protein and will investigate the hypothesis that:i) stabilized BOK contributes to apoptotic cell death under certain cellular stressesii) in addition to regulation of BOK stability by ERAD, BOK’s latent pro-apoptotic function is suppressed by alternative mechanism ways to control apoptotic cell death.We propose that BOK’s activity is modulated by post-translational modifications downstream from these cellular stresses that define its subcellular localization and protein-protein interactions. By characterizing the regulation of BOK in normal and cancer cells we will reveal BOK’s (patho-) physiological role and how BOK is engaged. This project will focus on the identification of novel molecular mechanisms regulating BOK’s pro-apoptotic function in cancer and in physiology.

癌症的治疗策略旨在诱导细胞死亡。因此，了解细胞如何激活或抑制促凋亡信号是开发有效抗癌疗法的关键问题。BCL2家族的亲凋亡和抗凋亡成员通过控制线粒体外膜透性（MOMP）过程在细胞存活与死亡的选择中起着至关重要的作用。MOMP的三种有效效应物是BAX、BAK和bcl -2相关的卵巢杀手（BOK）。与BAX和BAK形成鲜明对比的是，BOK不受抗凋亡BCL2家族成员（如BCL-2、BCL-xL、BCL-W、MCL-1）的调控。在迄今为止研究的大多数细胞系中，MOMP效应物BOK的促凋亡活性通过泛素介导的降解被抑制。因此，在具有“不稳定”BOK的细胞中，几乎检测不到这种蛋白质。在这些细胞系中，通过蛋白酶体抑制或过表达BOK来稳定BOK可导致细胞凋亡。这些和其他研究结果表明，BOK是一种组成活性的MOMP效应物，并且BOK的凋亡活性被er相关降解（ERAD）途径的细胞质臂的作用所抑制。相比之下，我们观察到一些器官和癌细胞系含有组成性“稳定”的BOK蛋白，这表明BOK的MOMP效应功能通过蛋白质体降解的另一种机制失活。我们的初步数据表明，某些细胞应激（例如，有丝分裂损伤，内质网应激）可以激活本构稳定的BOK，但如何发生尚不清楚。因此，本项目将探讨BOK对维持BOK蛋白稳定的细胞凋亡的影响，并将研究以下假设：i)稳定的BOK有助于在一定的细胞应激下凋亡细胞死亡ii)除了ERAD调节BOK稳定性外，BOK潜在的促凋亡功能还被其他机制方式抑制以控制凋亡细胞死亡。我们认为BOK的活性受到这些细胞应激下游翻译后修饰的调节，这些修饰定义了其亚细胞定位和蛋白质-蛋白质相互作用。通过表征BOK在正常细胞和癌细胞中的调节，我们将揭示BOK的（病理）生理作用以及BOK是如何参与的。本项目将重点研究BOK在肿瘤和生理上促凋亡功能的新分子机制。

项目成果

BRN2 suppresses apoptosis, reprograms DNA damage repair, and is associated with a high somatic mutation burden in melanoma

• DOI: 10.1101/gad.314633.118
• 发表时间: 2019-03-01
• 期刊: GENES & DEVELOPMENT
• 影响因子: 10.5
• 作者: Herbert, Katharine;Binet, Romuald;Goding, Colin R.
• 通讯作者: Goding, Colin R.