title: Proton-motive force stimulates the proteolytic activity of FtsH, a membrane-bound ATP-dependent protease in Escherichia coli.
abstract: FtsH is a membrane-bound, ATP-dependent metalloprotease in Escherichia coli that degrades some integral membrane proteins and cytoplasmic proteins. In this study, we show that FtsH-dependent degradation of both membrane-bound and soluble proteins is retarded when cells are treated with carbonyl cyanide-3-chlorophenylhydrazone or 2,4-dinitrophenol uncouplers, which dissipate the proton-motive force. In vitro casein degradation by membrane-integrated FtsH was stimulated by succinate, a respiratory substrate; this stimulation was counteracted by cyanide-3-chlorophenylhydrazone. Potassium thiocyanate, which specifically collapses Deltapsi, partially canceled the effect of succinate, but ammonium sulfate, which collapses DeltapH, showed little effect. These results indicate that the proton-motive force, in particular the Deltapsi component, plays a role in efficient degradation of substrates by FtsH in its native state. FtsH variants with altered transmembrane regions did not receive proton-motive force stimulation, suggesting that the proton-motive force activates FtsH, directly or indirectly, through the transmembrane region.
authors.affiliation: Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan. yakiyama@virus.kyoto-u.ac.jp
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Akiyama
mesh_terms: D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002462:Cell Membrane / Q000201:enzymology; D010450:Endopeptidases / Q000378:metabolism*; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008565:Membrane Proteins / Q000378:metabolism*; D010957:Plasmids; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; D011994:Recombinant Proteins; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D010450:Endopeptidases; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli; D000251:Adenosine Triphosphatases