Suppression of ftsH mutant phenotypes by overproduction of molecular chaperones.
Decreased intracellular levels of FtsH, a membrane-bound ATPase, led to retardation of growth and protein export, as well as to an abnormal translocation of alkaline phosphatase that had been attached to a cytoplasmic domain of a multispanning membrane protein, SecY. The last phenotype is designated Std (stop transfer defective). In this study, we examined the effects of overproduction of some molecular chaperones on the phenotypes of ftsH mutants. The growth retardation was partially suppressed by overproduction of GroEL/GroES (Hsp60/Hsp10) or HtpG (Hsp90), although these chaperones could not totally substitute for FtsH. Overproduction of HtpG specifically alleviated the Std phenotype, while that of GroEL/GroES alleviated the protein export defect of ftsH mutants. These results suggest that FtsH functions can be somehow compensated for when the cellular concentrations of some molecular chaperones increase.
Shirai
Y
Y
Department of Cell Biology, Kyoto University, Japan.
Akiyama
Y
Y
Ito
K
K
D049069:ATP-Dependent Proteases; D000251:Adenosine Triphosphatases / Q000235:genetics*; D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D001425:Bacterial Outer Membrane Proteins / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport / Q000235:genetics; D018835:Chaperonin 10 / Q000096:biosynthesis / Q000235:genetics; D018834:Chaperonin 60 / Q000096:biosynthesis / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics*; D029968:Escherichia coli Proteins; D018841:HSP90 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics*; D018832:Molecular Chaperones / Q000096:biosynthesis* / Q000235:genetics; D010641:Phenotype; D000069816:SEC Translocation Channels; D013489:Suppression, Genetic
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D018835:Chaperonin 10; D018834:Chaperonin 60; D029968:Escherichia coli Proteins; D018841:HSP90 Heat-Shock Proteins; C489352:HtpG protein, E coli; D008565:Membrane Proteins; D018832:Molecular Chaperones; D000069816:SEC Translocation Channels; C057841:SecY protein, E coli; C066720:HtpG protein, bacteria; D000469:Alkaline Phosphatase; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli; D000251:Adenosine Triphosphatases