title: The Enigmatic Esx Proteins: Looking Beyond Mycobacteria.
abstract: Bacteria export proteins across membranes using a range of transport machineries. Type VII secretion systems (T7SSs), originally described in mycobacteria, are now known to be widespread across diverse bacterial phyla. Recent studies have characterized secretion components and mechanisms of type VII secretion in pathogenic and environmental bacteria. A variety of functions have been attributed to T7SS substrates, including interactions with eukaryotes and with other bacteria. Here, we evaluate the growing body of knowledge on T7SSs, with focus on the nonmycobacterial systems, reviewing their phylogenetic distribution, structure and function in diverse settings.
authors.affiliation: Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK. Electronic address: m.unnikrishnan@warwick.ac.uk.
authors.forename: Meera
authors.initials: M
authors.lastname: Unnikrishnan
authors.affiliation: Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.
authors.forename: Chrystala
authors.initials: C
authors.lastname: Constantinidou
authors.affiliation: Division of Molecular Microbiology, University of Dundee, Dundee, UK.
authors.forename: Tracy
authors.initials: T
authors.lastname: Palmer
authors.affiliation: Division of Biomedical Sciences, Warwick Medical School, University of Warwick, Coventry, UK.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Pallen
mesh_terms: D000942:Antigens, Bacterial / Q000378:metabolism; D001412:Bacillus subtilis / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism; D054884:Host-Pathogen Interactions / Q000502:physiology; D009169:Mycobacterium tuberculosis / Q000235:genetics / Q000378:metabolism*; D021381:Protein Transport / Q000235:genetics / Q000502:physiology*; D013211:Staphylococcus aureus / Q000378:metabolism*; D000069377:Type VII Secretion Systems / Q000378:metabolism*
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D000069377:Type VII Secretion Systems
keywords: Esx; WXG100; toxin–antitoxin; type VII secretion