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Proton-motive force stimulates the proteolytic activity of FtsH, a membrane-bound ATP- dependent protease in Escherichia coli

By Yoshinori Akiyama

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 Δψ, partially canceled the effect of succinate, but ammonium sulfate, which collapses ΔpH, showed little effect. These results indicate that the proton-motive force, in particular the Δψ 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

Topics: Biological Sciences
Publisher: The National Academy of Sciences
Year: 2002
DOI identifier: 10.1073/pnas.122616899
OAI identifier: oai:pubmedcentral.nih.gov:123021
Provided by: PubMed Central
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