Hsp104, Hsp70, and Hsp40: a novel chaperone system that rescues previously aggregated proteins.
Hsp104 is a stress tolerance factor that promotes the reactivation of heat-damaged proteins in yeast by an unknown mechanism. Herein, we demonstrate that Hsp104 functions in this process directly. Unlike other chaperones, Hsp104 does not prevent the aggregation of denatured proteins. However, in concert with Hsp40 and Hsp70, Hsp104 can reactivate proteins that have been denatured and allowed to aggregate, substrates refractory to the action of other chaperones. Hsp104 cooperates with the chaperones present in reticulocyte lysates but not with DnaK of E. coli. We conclude that Hsp104 has a protein remodeling activity that acts on trapped, aggregated proteins and requires specific interactions with conventional chaperones to promote refolding of the intermediates it produces.
Howard Hughes Medical Institute and Department of Molecular Genetics and Cell Biology, The University of Chicago, Illinois 60637, USA.
J R
JR
Glover
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S
Lindquist
D000251:Adenosine Triphosphatases; D005656:Fungal Proteins / Q000378:metabolism*; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism*; D018832:Molecular Chaperones / Q000378:metabolism*; D011489:Protein Denaturation; D017510:Protein Folding; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D001616:beta-Galactosidase / Q000378:metabolism
D005656:Fungal Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; C070319:YDJ1 protein, S cerevisiae; C070972:HsP104 protein, S cerevisiae; D001616:beta-Galactosidase; D000251:Adenosine Triphosphatases; C095973:SSA1 protein, S cerevisiae