A tightly controlled turnover of membrane proteins is required for lipid bilayer stability, cell metabolism, and cell viability. Among the energy-dependent AAA proteases in Salmonella, FtsH is the only membrane-bound protease that contributes to the quality control of membrane proteins. FtsH preferentially degrades the C-terminus or N-terminus of misfolded, misassembled, or damaged proteins to maintain physiological functions. We found that FtsH hydrolyzes the Salmonella MgtC virulence protein when we substitute the MgtC 226 Trp, which is well conserved in other intracellular pathogens and normally protects MgtC from the FtsH-mediated proteolysis. Here we investigate a rule determining the FtsH-mediated proteolysis of the MgtC protein at Trp226 residue. Substitution of MgtC tryptophan 226 residue to alanine, glycine, or tyrosine leads to MgtC proteolysis in a manner dependent on the FtsH protease whereas substitution to phenylalanine, methionine, isoleucine, leucine, or valine resists MgtC degradation by FtsH. These data indicate that a large and hydrophobic side chain at 226 residue is required for protection from the FtsH-mediated MgtC proteolysis.
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http://dx.doi.org/10.1007/s12275-018-8245-6 | DOI Listing |
J Biol Chem
April 2024
Microbial Biology, Faculty of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany. Electronic address:
A promising yet clinically unexploited antibiotic target in difficult-to-treat Gram-negative bacteria is LpxC, the key enzyme in the biosynthesis of lipopolysaccharides, which are the major constituents of the outer membrane. Despite the development of dozens of chemically diverse LpxC inhibitor molecules, it is essentially unknown how bacteria counteract LpxC inhibition. Our study provides comprehensive insights into the response against five different LpxC inhibitors.
View Article and Find Full Text PDFMol Microbiol
January 2023
Microbial Biology, Ruhr University Bochum, Bochum, Germany.
The outer membrane (OM) of Gram-negative bacteria functions as an essential barrier and is characterized by an asymmetric bilayer with lipopolysaccharide (LPS) in the outer leaflet. The enzyme LpxC catalyzes the first committed step in LPS biosynthesis. It plays a critical role in maintaining the balance between LPS and phospholipids (PL), which are both derived from the same biosynthetic precursor.
View Article and Find Full Text PDFInt J Mol Sci
November 2020
Unit of Bacterial Genetics, Gdansk University of Technology, 80-233 Gdansk, Poland.
We previously showed that lipopolysaccharide (LPS) assembly requires the essential LapB protein to regulate FtsH-mediated proteolysis of LpxC protein that catalyzes the first committed step in the LPS synthesis. To further understand the essential function of LapB and its role in LpxC turnover, multicopy suppressors of Δ revealed that overproduction of HslV protease subunit prevents its lethality by proteolytic degradation of LpxC, providing the first alternative pathway of LpxC degradation. Isolation and characterization of an extragenic suppressor mutation that prevents lethality of Δ by restoration of normal LPS synthesis identified a frame-shift mutation after 377 aa in the essential gene designated , suggesting LapB and LapC act antagonistically.
View Article and Find Full Text PDFJ Microbiol
August 2018
Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin, 17104, Republic of Korea.
A tightly controlled turnover of membrane proteins is required for lipid bilayer stability, cell metabolism, and cell viability. Among the energy-dependent AAA proteases in Salmonella, FtsH is the only membrane-bound protease that contributes to the quality control of membrane proteins. FtsH preferentially degrades the C-terminus or N-terminus of misfolded, misassembled, or damaged proteins to maintain physiological functions.
View Article and Find Full Text PDFJ Biol Chem
July 2015
From Microbial Biology, Ruhr University Bochum, 44801 Bochum, Germany
Regulated proteolysis efficiently and rapidly adapts the bacterial proteome to changing environmental conditions. Many protease substrates contain recognition motifs, so-called degrons, that direct them to the appropriate protease. Here we describe an entirely new degron identified in the cytoplasmic N-terminal end of the membrane-anchored protein YfgM of Escherichia coli.
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