The human pathogen Streptococcus pyogenes releases lipoproteins as lipoprotein-rich membrane vesicles
| Autor: | Anna Rita Taddei, Massimiliano Biagini, Immaculada Margarit, Sandra Nuti, Simona Tavarini, Marco Becherelli, Giuseppe Teti, Alfredo Pezzicoli, Marirosa Mora, Marco Soriani, Manuela Garibaldi, Francesco Doro, Chiara Tani, Susanna Aprea, Rino Rappuoli, Ugo D'Oro, Guido Grandi, Nathalie Norais |
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| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
Streptococcus pyogenes
Lipoproteins Penicillins medicine.disease_cause Biochemistry Bacterial cell structure Analytical Chemistry chemistry.chemical_compound Membrane Microdomains Bacterial Proteins medicine Humans Molecular Biology Phosphatidylglycerol biology Research Vesicle Lipid microdomain biology.organism_classification Toll-Like Receptor 2 Culture Media Cell biology Molecular Weight HEK293 Cells Secretory protein chemistry Mutation lipids (amino acids peptides and proteins) Software Bacteria Lipoprotein |
| Popis: | Bacterial lipoproteins are attractive vaccine candidates because they represent a major class of cell surface-exposed proteins in many bacteria and are considered as potential pathogen-associated molecular patterns sensed by Toll-like receptors with built-in adjuvanticity. Although Gram-negative lipoproteins have been extensively characterized, little is known about Gram-positive lipoproteins. We isolated from Streptococcus pyogenes a large amount of lipoproteins organized in vesicles. These vesicles were obtained by weakening the bacterial cell wall with a sublethal concentration of penicillin. Lipid and proteomic analysis of the vesicles revealed that they were enriched in phosphatidylglycerol and almost exclusively composed of lipoproteins. In association with lipoproteins, a few hypothetical proteins, penicillin-binding proteins, and several members of the ExPortal, a membrane microdomain responsible for the maturation of secreted proteins, were identified. The typical lipidic moiety was apparently not necessary for lipoprotein insertion in the vesicle bilayer because they were also recovered from the isogenic diacylglyceryl transferase deletion mutant. The vesicles were not able to activate specific Toll-like receptor 2, indicating that lipoproteins organized in these vesicular structures do not act as pathogen-associated molecular patterns. In light of these findings, we propose to name these new structures Lipoprotein-rich Membrane Vesicles. |
| Databáze: | OpenAIRE |
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