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标题：Mycobacterial ESX-1 secretion system mediates host cell lysis through bacterium contact-dependent gross membrane disruptions
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作者：William H. Conrad ; Morwan M. Osman ; Jonathan K. Shanahan 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2017
卷号：114
期号：6
页码：1371-1376
DOI：10.1073/pnas.1620133114
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Mycobacterium tuberculosis and Mycobacterium marinum are thought to exert virulence, in part, through their ability to lyse host cell membranes. The type VII secretion system ESX-1 [6-kDa early secretory antigenic target (ESAT-6) secretion system 1] is required for both virulence and host cell membrane lysis. Both activities are attributed to the pore-forming activity of the ESX-1–secreted substrate ESAT-6 because multiple studies have reported that recombinant ESAT-6 lyses eukaryotic membranes. We too find ESX-1 of M. tuberculosis and M. marinum lyses host cell membranes. However, we find that recombinant ESAT-6 does not lyse cell membranes. The lytic activity previously attributed to ESAT-6 is due to residual detergent in the preparations. We report here that ESX-1–dependent cell membrane lysis is contact dependent and accompanied by gross membrane disruptions rather than discrete pores. ESX-1–mediated lysis is also morphologically distinct from the contact-dependent lysis of other bacterial secretion systems. Our findings suggest redirection of research to understand the mechanism of ESX-1–mediated lysis.
关键词：Mycobacterium tuberculosis ; Mycobacterium marinum ; ESAT-6 ; ESX-1 secretion system ; cell membrane lysis