title: Cold-shock RNA-binding protein CspR is also exposed to the surface of Enterococcus faecalis.
abstract: CspR has been characterized recently as a cold-shock RNA-binding protein in Enterococcus faecalis, a natural member of the gastro-intestinal tract capable of switching from a commensal relationship with the host to an important nosocomial pathogen. In addition to its involvement in the cold-shock response, CspR also plays a role in the long-term survival and virulence of E. faecalis. In the present study, we demonstrated that anti-CspR immune rabbit serum protected larvae of Galleria mellonella against a lethal challenge of the WT strain. These results suggested that CspR might have a surface location. This hypothesis was verified by Western blot that showed detection of CspR in the total as well as in the surface protein fraction. In addition, identification of surface polypeptides by proteolytic shaving of intact bacterial cells followed by liquid chromatography-MS-MS revealed that cold-shock proteins (EF1367, EF2939 and CspR) were present on the cell surface. Lastly, anti-CspR immune rabbit serum was used for immunolabelling and detected with colloidal gold-labelled goat anti-rabbit IgG in order to determine the immunolocalization of CspR on E. faecalis WT strain. Electron microscopy images confirmed that the cold-shock protein RNA-binding protein CspR was present in both cytoplasmic and surface parts of the cell. These data strongly suggest that CspR, in addition to being located intracellularly, is also present in the extracellular protein fraction of the cells and has important functions in the infection process of Galleria larvae.
authors: Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France.
authors: Charlotte
authors: C
authors: Michaux
authors: Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France.
authors: Luis Felipe Romero
authors: LFR
authors: Saavedra
authors: Plateforme Proteogen SFR ICORE 4206, Université de Caen Basse-Normandie, Caen, France.
authors: Fany
authors: F
authors: Reffuveille
authors: Centre de Microscopie Appliquée à la Biologie, Université de Caen Basse-Normandie IFR ICORE, Caen, France.
authors: Benoît
authors: B
authors: Bernay
authors: Equipe Antibio-résistance, Université de Caen Basse-Normandie, Caen, France.
authors: Didier
authors: D
authors: Goux
authors: Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France.
authors: Axel
authors: A
authors: Hartke
authors: Unité de Recherche Risques Microbiens (U2RM), Equipe Stress Virulence Université de Caen Basse-Normandie, Caen, France.
authors: Nicolas
authors: N
authors: Verneuil
authors: Centre for Microbial Diseases and Immunity Research, Department of Microbiology and Immunology, University of British Columbia, Vancouver, Canada.
authors: Jean-Christophe
authors: JC
authors: Giard
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002853:Chromatography, Liquid; D057773:Cold Shock Proteins and Peptides / Q000032:analysis*; D013293:Enterococcus faecalis / Q000737:chemistry*; D007150:Immunohistochemistry; D007915:Lepidoptera / Q000382:microbiology; D008565:Membrane Proteins / Q000032:analysis*; D016253:Microscopy, Immunoelectron; D016601:RNA-Binding Proteins / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D057773:Cold Shock Proteins and Peptides; D008565:Membrane Proteins; D016601:RNA-Binding Proteins