title: Hsp105 but not Hsp70 family proteins suppress the aggregation of heat-denatured protein in the presence of ADP.
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.
authors.affiliation: Department of Biochemistry, Kyoto Pharmaceutical University, 5 Nakauchi-cho, Misasagi, Yamashina-ku, Kyoto 607-8414, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamagishi
authors.forename: Keiichi
authors.initials: K
authors.lastname: Ishihara
authors.forename: Youhei
authors.initials: Y
authors.lastname: Saito
authors.forename: Takumi
authors.initials: T
authors.lastname: Hatayama
mesh_terms: D000244:Adenosine Diphosphate / Q000737:chemistry* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D001517:Coleoptera; D050957:HSP110 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006358:Hot Temperature; D006801:Humans; D007768:Lactalbumin / Q000031:analogs & derivatives / Q000378:metabolism; D008156:Luciferases / Q000737:chemistry* / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D011489:Protein Denaturation; D017434:Protein Structure, Tertiary; D011869:Radioligand Assay; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017384:Sequence Deletion
chemical_list: C494641:Dnajb1 protein, mouse; D050957:HSP110 Heat-Shock Proteins; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C097205:HSPH1 protein, human; C490783:Hsp105 protein, mouse; D011994:Recombinant Proteins; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D007768:Lactalbumin; D008156:Luciferases