title: Listeria monocytogenes phosphatidylinositol-specific phospholipase C has evolved for virulence by greatly reduced activity on GPI anchors.
abstract: Listeria monocytogenes phosphatidylinositol-specific phospholipase C (PI-PLC) plays a critical role in escape of this human pathogen from host cell vacuoles. Unlike classical bacterial PI-PLCs, the L. monocytogenes enzyme has very weak activity on glycosylphosphatidylinositol (GPI)-anchored proteins. Previous crystal structure analysis has revealed that a small beta-strand (Vb) is present in Bacillus cereus PI-PLC and is absent in the enzyme from L. monocytogenes. This Vb beta-strand in B. cereus PI-PLC forms contacts with the glycan linker of GPI anchors, which presumably increases its activity on GPI-anchored proteins. In this study, we show that, of all known bacterial PI-PLCs, those from listeriae are the only ones that lack the beta-strand. Expression by L. monocytogenes of B. cereus PI-PLC, which has strong activity on GPI-anchored proteins, inhibited bacterial escape from a vacuole and cell-to-cell spread, resulting in greatly reduced virulence in mice. Deletion of the Vb beta-strand from B. cereus PI-PLC abolished its ability to cleave GPI-anchored proteins, decreased its inhibitory effects, and increased its virulence in mice. These results strongly suggest that L. monocytogenes PI-PLC has evolved as an important determinant of L. monocytogenes pathogenesis by absence of the Vb beta-strand, thus leading to greatly reduced activity on GPI-anchored proteins.
authors.affiliation: Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
authors.forename: Zhengyu
authors.initials: Z
authors.lastname: Wei
authors.forename: Lauren A
authors.initials: LA
authors.lastname: Zenewicz
authors.forename: Howard
authors.initials: H
authors.lastname: Goldfine
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D008089:Listeria monocytogenes / Q000166:cytology / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity*; D051379:Mice; D008969:Molecular Sequence Data; D043265:Phosphatidylinositol Diacylglycerol-Lyase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054801:Phosphoinositide Phospholipase C; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D014774:Virulence
chemical_list: D017261:Glycosylphosphatidylinositols; D054801:Phosphoinositide Phospholipase C; D043265:Phosphatidylinositol Diacylglycerol-Lyase