title: Localization of protein kinase C epsilon to macrophage vacuoles perforated by Listeria monocytogenes cytolysin.
abstract: Three proteins secreted by Listeria monocytogenes facilitate escape from macrophage vacuoles: the cholesterol-dependent cytolysin listeriolysin O (LLO), a phosphoinositide-specific phospholipase C (PI-PLC) and a broad-range phospholipase C (PC-PLC). LLO and PI-PLC can activate several members of the protein kinase C (PKC) family during infection. PKCepsilon is a novel PKC that contributes to macrophage activation, defence against bacterial infection, and phagocytosis; however, a role for PKCepsilon in Lm infections has not been described. To study PKCepsilon dynamics, PKCepsilon-YFP chimeras were visualized in macrophages during Lm infection. PKCepsilon-YFP was recruited to forming vacuoles during macrophage phagocytosis of Lm and again later to fully formed Lm vacuoles. The PKCepsilon-YFP localization to the fully formed Lm vacuole was LLO-dependent but independent of PI-PLC or PC-PLC. PKCepsilon-YFP recruitment often followed LLO perforation of the membrane, as indicated by localization of PKCepsilon-YFP to Lm vacuoles after they released small fluorescent dyes into the cytoplasm. PKCepsilon-YFP recruitment to vesicles also followed phagocytosis of LLO-containing liposomes or osmotic lysis of endocytic vesicles, indicating that vacuole perforation by LLO was the chief cause of the PKCepsilon response. These studies implicate PKCepsilon in a cellular mechanism for recognizing damaged membranous organelles, including the disrupted vacuoles created when Lm escapes into cytoplasm.
authors.affiliation: Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
authors.forename: Lee M
authors.initials: LM
authors.lastname: Shaughnessy
authors.forename: Peter
authors.initials: P
authors.lastname: Lipp
authors.forename: Kyung-Dall
authors.initials: KD
authors.lastname: Lee
authors.forename: Joel A
authors.initials: JA
authors.lastname: Swanson
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000378:metabolism / Q000633:toxicity; D002460:Cell Line; D006360:Heat-Shock Proteins / Q000378:metabolism / Q000633:toxicity; D006460:Hemolysin Proteins / Q000378:metabolism / Q000633:toxicity; D008089:Listeria monocytogenes / Q000472:pathogenicity*; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008264:Macrophages / Q000201:enzymology* / Q000276:immunology / Q000382:microbiology* / Q000648:ultrastructure; D051379:Mice; D008856:Microscopy, Fluorescence; D051744:Protein Kinase C-epsilon / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D014617:Vacuoles / Q000201:enzymology*
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; D008164:Luminescent Proteins; D011993:Recombinant Fusion Proteins; C054562:yellow fluorescent protein, Bacteria; D051744:Protein Kinase C-epsilon; C038705:hlyA protein, Listeria monocytogenes