Abstract
Hsp105alpha and Hsp105beta are mammalian members of the Hsp105/110 family, a diverged subgroup of the Hsp70 family. Here, we show that Hsp105alpha and Hsp105beta bind non-native protein through the beta-sheet domain and suppress the aggregation of heat-denatured protein in the presence of ADP rather than ATP. In contrast, Hsc70/Hsp40 suppressed the aggregation of heat-denatured protein in the presence of ATP rather than ADP. Furthermore, the overexpression of Hsp105alpha but not Hsp70 in COS-7 cells rescued the inactivation of luciferase caused by ATP depletion. Thus, Hsp105/110 family proteins are suggested to function as a substitute for Hsp70 family proteins to suppress the aggregation of denatured proteins in cells under severe stress, in which the cellular ATP level decreases markedly.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Diphosphate / chemistry*
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Adenosine Diphosphate / metabolism
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Adenosine Triphosphate / metabolism
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Animals
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COS Cells
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Chlorocebus aethiops
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Coleoptera
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HSP110 Heat-Shock Proteins
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HSP40 Heat-Shock Proteins
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HSP70 Heat-Shock Proteins / biosynthesis
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HSP70 Heat-Shock Proteins / chemistry*
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HSP70 Heat-Shock Proteins / genetics
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HSP70 Heat-Shock Proteins / metabolism
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Hot Temperature
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Humans
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Lactalbumin / analogs & derivatives
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Lactalbumin / metabolism
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Luciferases / chemistry*
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Luciferases / metabolism
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Mice
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Phosphorylation
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Protein Denaturation
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Protein Structure, Tertiary
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Radioligand Assay
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Recombinant Proteins / pharmacology
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Sequence Deletion
Substances
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Dnajb1 protein, mouse
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HSP110 Heat-Shock Proteins
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HSP40 Heat-Shock Proteins
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HSP70 Heat-Shock Proteins
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HSPH1 protein, human
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Hsp105 protein, mouse
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Recombinant Proteins
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Adenosine Diphosphate
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Adenosine Triphosphate
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Lactalbumin
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Luciferases