title: Depletion of SecDF-YajC causes a decrease in the level of SecG: implication for their functional interaction.
abstract: SecA and an apparatus comprising SecYEG and SecDF-YajC complexes catalyze protein translocation across the Escherichia coli membrane. SecDF-YajC and SecG facilitate membrane insertion of SecA, which is the driving force for protein translocation. Here we report that SecDF-YajC depletion together with SecG depletion nearly completely inhibits protein translocation both in vivo and in vitro, although SecDF-YajC had been thought to be unnecessary for in vitro translocation. The level of SecG in membranes decreased to about half upon SecDF-YajC depletion and recovered to a normal level when SecDF-YajC was expressed. SecDF-YajC inhibited disulfide bond formation between two SecG molecules possessing a single cysteine residue. These results suggest functional interaction between SecDF-YajC and SecG.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Kato
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Nishiyama
authors.forename: Hajime
authors.initials: H
authors.lastname: Tokuda
mesh_terms: D000942:Antigens, Bacterial / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D019281:Dimerization; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D021381:Protein Transport; D000069816:SEC Translocation Channels; D022161:Transport Vesicles / Q000378:metabolism
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D000069816:SEC Translocation Channels; C499394:SecD protein, E coli; C489583:SecF protein, E coli; C088616:SecG protein, E coli; C116101:YajC protein, Brucella; C075767:secD protein, Bacteria; C075768:secF protein, Bacteria