Dnak, Dnaj and Grpe Form a Cellular Chaperone Machinery Capable of Repairing Heat-Induced Protein Damage
The EMBO Journal vol. 12 no. 1 1 pp.4137 - 4144, 1993 DnaK, DnaJ and GrpE form a cellular chaperone machinery capable of repairing heat-induced protein damage Hartwig Schroder', Thomas Langer2, At least for the Escherichia coli homologs DnaK and GroEL, Franz-Ulrich Hartl2 and Bernd Bukau1l3 ATP-dependent substrate release appears to be controlled by the specific cofactors DnaJ and GrpE (for DnaK) and IZentrum fur Molekulare Biologie, Universitat Heidelberg, INF 282, GroES (for GroEL) (Goloubinoff et al., 1989; Liberek D69120 Heidelberg, Germany and 2Program in Cellular Biochemistry et al., 1991; Martin et al., 1991). In the case of DnaJ and and Biophysics, Rockefeller Research Laboratory, Sloan Kettering Institute, 1275 York Avenue, New York, NY 10021, USA GrpE, these cofactors act co-operatively to stimulate the ATPase activity of DnaK (Liberek et al., 1991). 3Corresponding author Interestingly, DnaJ has the capability to bind protein Communicated by H.Bujard substrates independently of DnaK, such as DnaB helicase (Georgopoulos et al., 1990; Liberek et al., 1990), heat Members of the conserved Hsp7O chaperone family are shock transcription factor a32 (Gamer et al., 1992), XP assumed to constitute a main cellular system for the (Georgopoulos et al., 1990), plasmid P1-encoded RepA prevention and the amelioration of stress-induced protein (Wickner, 1990), and unfolded rhodanese (Langer et al., damage, though little direct evidence exists for this 1992). The functional significance of this substrate binding function. We investigated the roles of the DnaK (Hsp7O), by DnaJ is unclear. DnaJ and GrpE chaperones of Escherichia coli in Given their capacity to assist protein folding, it is not prevention and repair of thermally induced protein surprising that Hsp7O chaperones have multiple roles in the damage using firefly luciferase as a test substrate.
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