Enhanced export of beta-galactosidase fusion proteins in prlF mutants is Lon dependent.

摘要: We have used fusions of the outer membrane protein LamB to beta-galactosidase (encoded by lacZ) study export process. This LamB-LacZ hybrid blocks when synthesized at high levels, as evidenced inducer (maltose) sensitivity, a phenomenon termed LacZ jamming. The prlF1 mutation relieves jamming and allows localization fusion noncytoplasmic compartment. similar alleles are gain-of-function mutations. Null mutations in this gene confer no obvious phenotypes. Extragenic suppressors prlF allele been isolated order understand how product affects all lon null mutations, they epistatic phenotypes tested. Lon protease activity has measured cells shown be increased. However, synthesis is not increased background, suggesting previously unidentified mechanism activation. Further analysis reveals that activates degradation cytoplasmically localized precursors protease-dependent manner. It proposed accumulation during conditions titrates an essential component(s), possibly chaperone. Increased Lon-dependent precursor would free component, thus allowing under conditions.