{"title":"Entangling roles of cholesterol-dependent interaction and cholesterol-mediated lipid phase heterogeneity in regulating listeriolysin O pore-formation.","authors":"Kusum Lata,Gregor Anderluh,Kausik Chattopadhyay","doi":"10.1042/bcj20240184","DOIUrl":null,"url":null,"abstract":"Cholesterol-dependent cytolysins (CDCs) are the distinct class of β-barrel pore-forming toxins (β-PFTs) that attack eukaryotic cell membranes, and form large, oligomeric, transmembrane β-barrel pores. Listeriolysin O (LLO) is a prominent member in the CDC family. As documented for the other CDCs, membrane cholesterol is essential for the pore-forming functionality of LLO. However, it remains obscure how exactly cholesterol facilitates its pore formation. Here, we show that cholesterol promotes both membrane-binding and oligomerization of LLO. We demonstrate cholesterol not only facilitates membrane-binding, it also enhances the saturation threshold of LLO-membrane association, and alteration of the cholesterol-recognition motif (CRM) in the LLO mutant (LLOT515G-L516G) compromises its pore-forming efficacy. Interestingly, such defect of LLOT515G-L516G could be rescued in the presence of higher membrane cholesterol levels, suggesting cholesterol can augment the pore-forming efficacy of LLO even in the absence of a direct toxin-cholesterol interaction. Furthermore, we find the membrane-binding and pore-forming abilities of LLOT515G-L516G, but not those of LLO, correlate with the cholesterol-dependent rigidity/ordering of the membrane lipid bilayer. Our data further suggest that the line tension derived from the lipid phase heterogeneity of the cholesterol-containing membranes could play a pivotal role in LLO function, particularly in the absence of cholesterol binding. Therefore, in addition to its receptor-like role, we conclude cholesterol can further facilitate the pore-forming, membrane-damaging functionality of LLO by asserting the optimal physicochemical environment in membranes. To the best of our knowledge, this aspect of the cholesterol-mediated regulation of the CDC mode of action has not been appreciated thus far.","PeriodicalId":8825,"journal":{"name":"Biochemical Journal","volume":null,"pages":null},"PeriodicalIF":4.4000,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Biochemical Journal","FirstCategoryId":"99","ListUrlMain":"https://doi.org/10.1042/bcj20240184","RegionNum":3,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"BIOCHEMISTRY & MOLECULAR BIOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
Cholesterol-dependent cytolysins (CDCs) are the distinct class of β-barrel pore-forming toxins (β-PFTs) that attack eukaryotic cell membranes, and form large, oligomeric, transmembrane β-barrel pores. Listeriolysin O (LLO) is a prominent member in the CDC family. As documented for the other CDCs, membrane cholesterol is essential for the pore-forming functionality of LLO. However, it remains obscure how exactly cholesterol facilitates its pore formation. Here, we show that cholesterol promotes both membrane-binding and oligomerization of LLO. We demonstrate cholesterol not only facilitates membrane-binding, it also enhances the saturation threshold of LLO-membrane association, and alteration of the cholesterol-recognition motif (CRM) in the LLO mutant (LLOT515G-L516G) compromises its pore-forming efficacy. Interestingly, such defect of LLOT515G-L516G could be rescued in the presence of higher membrane cholesterol levels, suggesting cholesterol can augment the pore-forming efficacy of LLO even in the absence of a direct toxin-cholesterol interaction. Furthermore, we find the membrane-binding and pore-forming abilities of LLOT515G-L516G, but not those of LLO, correlate with the cholesterol-dependent rigidity/ordering of the membrane lipid bilayer. Our data further suggest that the line tension derived from the lipid phase heterogeneity of the cholesterol-containing membranes could play a pivotal role in LLO function, particularly in the absence of cholesterol binding. Therefore, in addition to its receptor-like role, we conclude cholesterol can further facilitate the pore-forming, membrane-damaging functionality of LLO by asserting the optimal physicochemical environment in membranes. To the best of our knowledge, this aspect of the cholesterol-mediated regulation of the CDC mode of action has not been appreciated thus far.
期刊介绍:
Exploring the molecular mechanisms that underpin key biological processes, the Biochemical Journal is a leading bioscience journal publishing high-impact scientific research papers and reviews on the latest advances and new mechanistic concepts in the fields of biochemistry, cellular biosciences and molecular biology.
The Journal and its Editorial Board are committed to publishing work that provides a significant advance to current understanding or mechanistic insights; studies that go beyond observational work using in vitro and/or in vivo approaches are welcomed.
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