Heat shock induction by a misassembled cytoplasmic membrane protein complex in Escherichia coli

Molecular Microbiology
M MourezE Dassa

Abstract

We analysed the effects of the overproduction of parts or all of a multisubunit ATP-binding cassette (ABC) transporter, the MalFGK2 complex, involved in the uptake of maltose and maltodextrins in Escherichia coli. We found that production of the MalF protein alone was inducing the phtrA promoter, which is under the control of a recently discovered sigma factor, sigma24, involved in the response to extracytoplasmic stresses. The production level, stability and localization of MalF were not altered when produced without its partners, suggesting that the protein was correctly inserted in the membrane. Our results indicate that a large periplasmic loop located between the third and fourth transmembrane segment of MalF, the L3 loop, is responsible for phtrA induction: (i) deleted MalF proteins with no L3 loop or with a L3 loop lacking 120 amino acids do not induce the phtrA promoter; (ii) the export to the periplasm of the L3 loop alone or fused to MalE induces the phtrA promoter. Moreover, the proteolytic sensitivity of MalF is different when it is produced alone and when MalF and MalG are produced together, suggesting a change in the conformation and/or accessibility of MalF. These results suggest that some inner membrane proteins...Continue Reading

Citations

Jun 26, 2001·Research in Microbiology·E Schneider
Sep 4, 2007·Trends in Microbiology·Sung-Jae LeeWinfried Boos
Jan 17, 2008·BMC Evolutionary Biology·Kenneth M NollDhaval M Nanavati
Feb 3, 2015·Biochemistry·Olga V MakhlynetsIvan V Korendovych
Nov 19, 2011·FEMS Microbiology Letters·Sabine HunkeVolker S Müller
Jun 26, 2002·Genes to Cells : Devoted to Molecular & Cellular Mechanisms·Nobuyuki ShimohataYoshinori Akiyama
Mar 27, 1999·Journal of Bacteriology·M I TapiaE Dassa
Dec 15, 2005·The Journal of Biological Chemistry·Martin L DausErwin Schneider

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