A rule governing the FtsH-mediated proteolysis of the MgtC virulence protein from Salmonella enterica serovar Typhimurium
Jonghyun Baek, Eunna Choi, and Eun-Jin Lee
Department of Genetic Engineering and Graduate School of Biotechnology, College of Life Sciences, Kyung Hee University, Yongin 17104, Republic of Korea
Journal of Microbiology, 56(8),565–570, 2018,
mgtC, FtsH protease, post-translational regulation
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 226th
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 FtsHmediated
proteolysis of the MgtC protein at Trp226 residue.
Substitution of MgtC tryptophan 226th 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 226th residue is required for
protection from the FtsH-mediated MgtC proteolysis.