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The Listeria monocytogenes hemolysin has an acidic pH optimum to compartmentalize activity and prevent damage to infected host cells
被引:206
作者:
Glomski, IJ
Gedde, MM
Tsang, AW
Swanson, JA
Portnoy, DA
机构:
[1] Univ Calif Berkeley, Dept Mol & Cell Biol, Berkeley, CA 94720 USA
[2] Univ Calif Berkeley, Sch Publ Hlth, Berkeley, CA 94720 USA
[3] Univ Michigan, Sch Med, Dept Microbiol & Immunol, Ann Arbor, MI 48109 USA
关键词:
cytolysins;
phagosome;
virulence;
molecular evolution;
macrophages;
D O I:
10.1083/jcb.200201081
中图分类号:
Q2 [细胞生物学];
学科分类号:
071009 ;
090102 ;
摘要:
Listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from a phagosome and grows in the host cell cytosol. The pore-forming cholesterol-dependent cytolysin, listeriolysin O (LLO), mediates bacteria] escape from vesicles and is similar to10-fold more active at an acidic than neutral pH. By swapping dissimilar residues from a pH-insensitive orthologue, perfringolysin 0 (PFO), we identified leucine 461 as unique to pathogenic Listeria and responsible for the acidic pH optimum of LLO. Conversion of leucine 461 to the threonine present in PFO increased the hemolytic activity of LLO almost 10-fold at a neutral pH. L. monocytogenes synthesizing LLO L461T, expressed from its endogenous site on the bacterial chromosome, resulted in a 100-fold virulence defect in the mouse listeriosis model. These bacteria escaped from acidic phagosomes and initially grew normally in cells and spread cell to cell, but prematurely permeabilized the host membrane and killed the cell. These data show that the acidic pH optimum of LLO results from an adaptive mutation that acts to limit cytolytic activity to acidic vesicles and prevent damage in the host cytosol, a strategy also used by host cells to compartmentalize lysosomal hydrolases.
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页码:1029 / 1038
页数:10
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