title: YfgM is an ancillary subunit of the SecYEG translocon in Escherichia coli.
abstract: Protein secretion in Gram-negative bacteria is essential for both cell viability and pathogenesis. The vast majority of secreted proteins exit the cytoplasm through a transmembrane conduit called the Sec translocon in a process that is facilitated by ancillary modules, such as SecA, SecDF-YajC, YidC, and PpiD. In this study we have characterized YfgM, a protein with no annotated function. We found it to be a novel ancillary subunit of the Sec translocon as it co-purifies with both PpiD and the SecYEG translocon after immunoprecipitation and blue native/SDS-PAGE. Phenotypic analyses of strains lacking yfgM suggest that its physiological role in the cell overlaps with the periplasmic chaperones SurA and Skp. We, therefore, propose a role for YfgM in mediating the trafficking of proteins from the Sec translocon to the periplasmic chaperone network that contains SurA, Skp, DegP, PpiD, and FkpA.
authors.affiliation: From the Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Götzke
authors.affiliation: From the Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Isolde
authors.initials: I
authors.lastname: Palombo
authors.affiliation: From the Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Claudio
authors.initials: C
authors.lastname: Muheim
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaires, CNRS, and Université Paul Sabatier, 31062 Toulouse, France, and.
authors.forename: Elsa
authors.initials: E
authors.lastname: Perrody
authors.affiliation: Laboratoire de Microbiologie et Génétique Moléculaires, CNRS, and Université Paul Sabatier, 31062 Toulouse, France, and.
authors.forename: Pierre
authors.initials: P
authors.lastname: Genevaux
authors.affiliation: Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare, Spemann Graduate School of Biology and Medicine, University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: Renuka
authors.initials: R
authors.lastname: Kudva
authors.affiliation: Institute of Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare, Spemann Graduate School of Biology and Medicine, University of Freiburg, D-79104 Freiburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Müller
authors.affiliation: From the Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden, ddaley@dbb.su.se.
authors.forename: Daniel O
authors.initials: DO
authors.lastname: Daley
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000172:deficiency / Q000235:genetics; D004926:Escherichia coli / Q000166:cytology / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D018832:Molecular Chaperones / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress; D019897:Periplasm / Q000378:metabolism; D021122:Protein Subunits / Q000378:metabolism*; D021381:Protein Transport; D000069816:SEC Translocation Channels
chemical_list: D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D021122:Protein Subunits; D000069816:SEC Translocation Channels; C000592363:YfgM protein, E coli; C072721:Skp protein, E coli
keywords: BN-PAGE; Escherichia coli (E. coli); Membrane Biogenesis; Membrane Protein; Periplasmic Chaperones; Protein Secretion; Protein Translocation; SecYEG Translocon