{"title":"Preferred inhibition of pro-apoptotic Bak by BclxL via a two-step mechanism.","authors":"Kira D Leitl, Laura E Sperl, Franz Hagn","doi":"10.1016/j.celrep.2024.114526","DOIUrl":null,"url":null,"abstract":"<p><p>Bak is a pore-forming Bcl2 protein that induces apoptosis at the outer mitochondrial membrane, which can either proceed via Bak oligomerization or be inhibited by anti-apoptotic Bcl2 proteins, such as BclxL. BclxL is very efficient in inhibiting Bak pore formation, but the mechanistic basis of this preferred interaction has remained enigmatic. Here, we identify Bakα1 as a second binding site for BclxL and show that it specifically interacts with the Bcl2-homology (BH)3 binding groove of BclxL. The affinity between BclxL and Bakα1 is weaker than with Bak-BH3, suggesting that Bakα1, being exposed early in the pore-forming trajectory, transiently captures BclxL, which subsequently transitions to the proximal BH3 site. Bak variants where the initial transient interaction with BclxL is modulated show a markedly altered response to BclxL inhibition. This work contributes to a better mechanistic understanding of the fine-tuned interactions between different players of the Bcl2 protein family.</p>","PeriodicalId":9798,"journal":{"name":"Cell reports","volume":null,"pages":null},"PeriodicalIF":7.5000,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cell reports","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1016/j.celrep.2024.114526","RegionNum":1,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/7/22 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"CELL BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Bak is a pore-forming Bcl2 protein that induces apoptosis at the outer mitochondrial membrane, which can either proceed via Bak oligomerization or be inhibited by anti-apoptotic Bcl2 proteins, such as BclxL. BclxL is very efficient in inhibiting Bak pore formation, but the mechanistic basis of this preferred interaction has remained enigmatic. Here, we identify Bakα1 as a second binding site for BclxL and show that it specifically interacts with the Bcl2-homology (BH)3 binding groove of BclxL. The affinity between BclxL and Bakα1 is weaker than with Bak-BH3, suggesting that Bakα1, being exposed early in the pore-forming trajectory, transiently captures BclxL, which subsequently transitions to the proximal BH3 site. Bak variants where the initial transient interaction with BclxL is modulated show a markedly altered response to BclxL inhibition. This work contributes to a better mechanistic understanding of the fine-tuned interactions between different players of the Bcl2 protein family.
期刊介绍:
Cell Reports publishes high-quality research across the life sciences and focuses on new biological insight as its primary criterion for publication. The journal offers three primary article types: Reports, which are shorter single-point articles, research articles, which are longer and provide deeper mechanistic insights, and resources, which highlight significant technical advances or major informational datasets that contribute to biological advances. Reviews covering recent literature in emerging and active fields are also accepted.
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