Das Kushal Kumar, Shalaby Raed, García-Sáez Ana J
Interfaculty Institute of Biochemistry, Eberhard Karls University Tübingen , Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
Max Planck Institute for Intelligent Systems , Heisenbergstr. 3, 70569 Stuttgart, Germany.
ACS Chem Biol. 2017 Apr 21;12(4):989-1000. doi: 10.1021/acschembio.6b01084. Epub 2017 Feb 17.
The prosurvival Bcl-2 proteins exhibit a specific pattern of interactions with BH3-only proteins that determines the cellular dependence on apoptotic stress. This specificity is crucial for the development of BH3 mimetics, a class of anticancer molecules based on the BH3 domain with promising activity in clinical trials. Although complex formation mainly takes place in the mitochondrial outer membrane, most studies so far addressed the interaction between BH3 peptides and truncated Bcl-2 proteins in solution. As a consequence, quantitative understanding of the sequence specificity determinants of BH3 peptides in the membrane environment is missing. Here, we tackle this issue by systematically quantifying the ability of BH3 peptides to compete for the complexes between cBid and Bcl-xL in giant unilamellar vesicles and compare it with solution and mitochondria. We show that the BH3 peptides derived from Hrk, Bim, Bid, and Bad are the most efficient in disrupting cBid/Bcl-xL complexes in the membrane, which correlates with their activity in mitochondria. Our findings support the targeting to the membrane of small molecules that bind Bcl-2 proteins as a strategy to improve their efficiency.
促生存Bcl-2蛋白与仅含BH3结构域的蛋白呈现出特定的相互作用模式，这种模式决定了细胞对凋亡应激的依赖性。这种特异性对于BH3模拟物的开发至关重要，BH3模拟物是一类基于BH3结构域的抗癌分子，在临床试验中具有可观的活性。尽管复合物的形成主要发生在线粒体外膜，但迄今为止，大多数研究都关注BH3肽与溶液中截短的Bcl-2蛋白之间的相互作用。因此，目前尚缺乏对膜环境中BH3肽序列特异性决定因素的定量理解。在此，我们通过系统地量化BH3肽在巨型单层囊泡中竞争cBid与Bcl-xL之间复合物的能力来解决这一问题，并将其与溶液和线粒体中的情况进行比较。我们发现，源自Hrk、Bim、Bid和Bad的BH3肽在破坏膜中的cBid/Bcl-xL复合物方面效率最高，这与其在线粒体中的活性相关。我们的研究结果支持将结合Bcl-2蛋白的小分子靶向到膜上，作为提高其效率的一种策略。
