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Listeriolysin O: cholesterol inhibits cytolysis but not binding to cellular membranes
Author(s) -
Jacobs Thomas,
Darji Ayub,
Frahm Nicole,
Rohde Manfred,
Wehland Jürgen,
Chakraborty Trinad,
Weiss Siegfried
Publication year - 1998
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1046/j.1365-2958.1998.00858.x
Subject(s) - listeriolysin o , cholesterol oxidase , biology , haemolysis , cytolysis , cholesterol , cytolysin , membrane , lysis , biochemistry , toxin , lytic cycle , cytotoxicity , listeria monocytogenes , bacteria , in vitro , virology , listeria , genetics , virus , virulence , gene , immunology
Listeriolysin O (LLO) binds to cholesterol‐containing membranes in which it oligomerizes to form pores. Preincubation of the toxin with cholesterol is known to inhibit haemolysis, whereas the oxidized form of cholesterol has no inhibitory effect. Using immunoblot analyses and flow cytometry we demonstrate that preincubation with cholesterol does not influence binding of the listeriolysin–cholesterol complex to red blood cells, eukaryotic cells or artificial membranes. Lytic activity of membrane‐bound LLO inactivated by cholesterol can be restored by enzymatic treatment with cholesterol oxidase. To determine the step at which cholesterol inhibits lytic activity, we looked for pore formation using electron microscopy. Pores formed by purified listeriolysin could be directly visualized using erythrocyte ghosts. This property was lost upon incubation of the toxin with cholesterol. Quantitative analysis strongly suggest that inhibition of lysis by cholesterol is not due to decreased binding of listeriolysin to target membranes, but rather to an interference with a subsequent step leading to polymerization of the toxin.