A protease complex in the Escherichia coli plasma membrane: HflKC (HflA) forms a complex with FtsH (HflB), regulating its proteolytic activity against SecY.

摘要: Escherichia coli FtsH (HflB), a membrane-bound ATPase is required for proteolytic degradation of uncomplexed forms the protein translocase SecY subunit. We have now isolated SecY-stabilizing mutations that cause an amino acid substitution in HflK-HflC membrane complex. Although HflKC was believed to activity against lambda cII protein, deletion hflK-hflC did not stabilize SecY. Instead, mutant alleles were partially dominant and overexpression ftsH suppressed mutational effects, suggesting proteins antagonized These results raise possibility even wild-type acts antagonize FtsH. Consistent with this notion, hflkC null mutation accelerated SecY24 protein. Furthermore cross-linking, co-immunoprecipitation, histidine-tagging gel filtration experiments all indicated form complex vivo vitro. Finally, purified inhibited SecY-degrading indicate modulated negatively by its association HflKC.