title: Secretion and subcellular localizations of bacterial proteins: a semantic awareness issue.
abstract: Extracellular proteins are a subject of intense interest because of their essential roles in bacterial lifestyles. However, several terms related to secretion are used confusingly in the literature, and this is a topical issue in genomics and proteomics. Defining a secreted protein as actively translocated via a secretion system, here, we put into perspective that homologous translocation systems can result in radically different subcellular localizations of a secreted protein. We propose using standardized nomenclature for secretion systems from type I to type VIII for Gram-negative bacteria only, whereas the terms 'Sec' (secretion), 'Tat' (twin-arginine translocation), 'FEA' (flagella export apparatus), 'FPE' (fimbrilin-protein exporter), 'holin' (hole forming) and 'Wss' (WXG100 secretion system) should be applied to translocation systems across the cytoplasmic membrane of both Gram-positive and Gram-negative bacteria. Finally, we discuss why the term 'exoproteome' should be favoured over 'secretome' when describing the subset of proteins present in the extracellular milieu.
authors.affiliation: INRA (Institut National de la Recherche Agronomique), UR454 Microbiologie, Centre de Recherche Clermont-Ferrand, F-63122 Saint-Genès Champanelle, France. mdesvaux@clermont.inra.fr
authors.forename: Mickaël
authors.initials: M
authors.lastname: Desvaux
authors.forename: Michel
authors.initials: M
authors.lastname: Hébraud
authors.forename: Régine
authors.initials: R
authors.lastname: Talon
authors.forename: Ian R
authors.initials: IR
authors.lastname: Henderson
mesh_terms: D001419:Bacteria / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D005110:Extracellular Space / Q000378:metabolism*; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins