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

AUTOR(ES)

Akiyama, Yoshinori

FONTE

The National Academy of Sciences

RESUMO

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.

Documentos Relacionados

• Escherichia coli FtsH is a membrane-bound, ATP-dependent protease which degrades the heat-shock transcription factor sigma 32.
• A Membrane-Bound Archaeal Lon Protease Displays ATP-Independent Proteolytic Activity towards Unfolded Proteins and ATP-Dependent Activity for Folded Proteins
• Incorporation of beef heart cytochrome c oxidase as a proton-motive force-generating mechanism in bacterial membrane vesicles.
• Proton conduction by subunit a of the membrane-bound ATP synthase of Escherichia coli revealed after induced overproduction.
• Solubilization of Escherichia coli nitrate reductase by a membrane-bound protease.