1. SecA Localization and SecA-Dependent Secretion Occurs at New Division Septa in Group B Streptococcus
- Author
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Elise Caliot, Sara Brega, Shaynoor Dramsi, Patrick Trieu-Cuot, Biologie des Bactéries pathogènes à Gram-positif, Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS), and Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS)
- Subjects
Amino Acid Motifs ,Immunofluorescence ,lcsh:Medicine ,Fluorescent Antibody Technique ,MESH: Amino Acid Sequence ,Substrate Specificity ,MESH: Membrane Transport Proteins ,MESH: Recombinant Proteins ,MESH: Amino Acid Motifs ,chemistry.chemical_compound ,Cell Wall ,Sortase ,MESH: Animals ,Bacterial Physiology ,lcsh:Science ,MESH: Bacterial Secretion Systems ,Bacterial Secretion Systems ,MESH: Fluorescent Antibody Technique ,MESH: Bacterial Proteins ,Peptide sequence ,Adenosine Triphosphatases ,0303 health sciences ,Multidisciplinary ,Streptococci ,Recombinant Proteins ,Bacterial Pathogens ,Bacterial Biochemistry ,Protein Transport ,Sortase A ,Medicine ,Infectious diseases ,MESH: Cell Division ,Group B streptococcal infection ,MESH: Protein Sorting Signals ,Cell Division ,Subcellular Fractions ,Research Article ,Signal peptide ,MESH: Protein Transport ,MESH: Mutation ,Molecular Sequence Data ,Immunology ,Bacterial diseases ,Protein Sorting Signals ,Biology ,Microbiology ,Streptococcus agalactiae ,03 medical and health sciences ,MESH: Cell Wall ,Bacterial Proteins ,MESH: Bacterial Capsules ,MESH: Adenosine Triphosphatases ,Animals ,Secretion ,Amino Acid Sequence ,Bacterial Capsules ,Secretory pathway ,030304 developmental biology ,SecA Proteins ,MESH: Molecular Sequence Data ,030306 microbiology ,lcsh:R ,Cell Membrane ,Membrane Transport Proteins ,Bacteriology ,MESH: Streptococcus agalactiae ,[SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology ,Molecular biology ,MESH: Extracellular Space ,Membrane protein ,chemistry ,MESH: Subcellular Fractions ,Mutation ,Immunologic Techniques ,lcsh:Q ,MESH: Substrate Specificity ,Peptidoglycan ,Extracellular Space ,SEC Translocation Channels ,MESH: Cell Membrane - Abstract
International audience; Exported proteins of Streptococcus agalactiae (GBS), which include proteins localized to the bacterial surface or secreted into the extracellular environment, are key players for commensal and pathogenic interactions in the mammalian host. These proteins are transported across the cytoplasmic membrane via the general SecA secretory pathway and those containing the so-called LPXTG sorting motif are covalently attached to the peptidoglycan by sortase A. How SecA, sortase A, and LPXTG proteins are spatially distributed in GBS is not known. In the close relative Streptococcus pyogenes, it was shown that presence of the YSIRKG/S motif (literally YSIRKX3Gx2S) in the signal peptide (SP) constitutes the targeting information for secretion at the septum. Here, using conventional and deconvolution immunofluorescence analyses, we have studied in GBS strain NEM316 the localization of SecA, SrtA, and the secreted protein Bsp whose signal peptide contains a canonical YSIRKG/S motif (YSLRKykfGlaS). Replacing the SP of Bsp with four other SPs containing or not the YSIRKG/S motif did not alter the localized secretion of Bsp at the equatorial ring. Our results indicate that secretion and cell wall-anchoring machineries are localized at the division septum. Cell wall- anchored proteins displayed polar (PilB, Gbs0791), punctuate (CspA) or uniform distribution (Alp2) on the bacterial surface. De novo secretion of Gbs0791 following trypsin treatment indicates that it is secreted at the septum, then redistributed along the lateral sides, and finally accumulated to the poles. We conclude that the ±YSIRK SP rule driving compartimentalized secretion is not true in S. agalactiae.
- Published
- 2013