PMID:7900997

Citation	Schröder, H, Langer, T, Hartl, FU and Bukau, B (1993) DnaK, DnaJ and GrpE form a cellular chaperone machinery capable of repairing heat-induced protein damage. EMBO J. 12:4137-44
Abstract	Members of the conserved Hsp70 chaperone family are assumed to constitute a main cellular system for the prevention and the amelioration of stress-induced protein damage, though little direct evidence exists for this function. We investigated the roles of the DnaK (Hsp70), DnaJ and GrpE chaperones of Escherichia coli in prevention and repair of thermally induced protein damage using firefly luciferase as a test substrate. In vivo, luciferase was rapidly inactivated at 42 degrees C, but was efficiently reactivated to 50% of its initial activity during subsequent incubation at 30 degrees C. DnaK, DnaJ and GrpE did not prevent luciferase inactivation, but were essential for its reactivation. In vitro, reactivation of heat-inactivated luciferase to 80% of its initial activity required the combined activity of DnaK, DnaJ and GrpE as well as ATP, but not GroEL and GroES. DnaJ associated with denatured luciferase, targeted DnaK to the substrate and co-operated with DnaK to prevent luciferase aggregation at 42 degrees C, an activity that was required for subsequent reactivation. The protein repair function of DnaK, GrpE and, in particular, DnaJ is likely to be part of the role of these proteins in regulation of the heat shock response.
Links	PubMed PMC413706
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; Chaperonins; Enzyme Activation; Enzyme Reactivators/metabolism; Escherichia coli/metabolism; Escherichia coli Proteins; Genes, Bacterial; HSP40 Heat-Shock Proteins; HSP70 Heat-Shock Proteins; Heat-Shock Proteins/genetics; Heat-Shock Proteins/metabolism; Hot Temperature; Luciferases/metabolism; Multigene Family; Protein Denaturation; Proteins/genetics; Proteins/metabolism; Recombinant Proteins/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
ECOLI:DNAJ	acts_upstream_of_or_within	GO:0051085: chaperone cofactor-dependent protein refolding	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	acts_upstream_of_or_within	GO:0051085: chaperone cofactor-dependent protein refolding	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	acts_upstream_of_or_within	GO:0009408: response to heat	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	acts_upstream_of_or_within	GO:0034620: cellular response to unfolded protein	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	involved_in	GO:0009408: response to heat	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	involved_in	GO:0034620: cellular response to unfolded protein	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
ECOLI:DNAK	involved_in	GO:0051085: chaperone cofactor-dependent protein refolding	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete
BIFAP:K4INZ2		GO:0006457: protein folding	ECO:0000314:		P		See Figure 1(A) of associated PMID	complete CACAO 9576
ECOLI:DNAJ	involved_in	GO:0051085: chaperone cofactor-dependent protein refolding	ECO:0000314: direct assay evidence used in manual assertion		P		Seeded From UniProt	complete

References

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