title: Role of the mitochondrial DnaJ homologue, Mdj1p, in the prevention of heat-induced protein aggregation.
abstract: The role of the mitochondrial Hsp70 system in the prevention of heat-induced protein aggregation was studied in isolated mitochondria from Saccharomyces cerevisiae. Firefly luciferase was employed as a thermolabile tester protein. After shift to 40 degrees Celsius transient increase of mt-Hsp70/luciferase complex was observed, which required functional Mdj1p and Mge1p, the mitochondrial homologues of DnaJ and GrpE. The kinetics of luciferase aggregation, however, were not influenced by mutations in either mt-Hsp70 or Mge1p. Only the absence of Mdj1p led to enhanced protein aggregation. Thus, a central role in the transient protection against heat stress is attributed to this mitochondrial DnaJ homologue.
authors.affiliation: Institut für Physiologische Chemie, München, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Prip-Buus
authors.forename: B
authors.initials: B
authors.lastname: Westerman
authors.forename: M
authors.initials: M
authors.lastname: Schmitt
authors.forename: T
authors.initials: T
authors.lastname: Langer
authors.forename: W
authors.initials: W
authors.lastname: Neupert
authors.forename: E
authors.initials: E
authors.lastname: Schwarz
mesh_terms: D001426:Bacterial Proteins; D002352:Carrier Proteins / Q000502:physiology; D005656:Fungal Proteins / Q000235:genetics / Q000502:physiology*; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D006360:Heat-Shock Proteins / Q000235:genetics / Q000502:physiology*; D018869:Heat-Shock Response / Q000502:physiology*; D008156:Luciferases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology*; D026901:Membrane Transport Proteins; D008928:Mitochondria / Q000502:physiology; D033681:Mitochondrial Membrane Transport Proteins; D018832:Molecular Chaperones; D009154:Mutation; D012441:Saccharomyces cerevisiae / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D005656:Fungal Proteins; C068113:GrpE protein, Bacteria; D050956:HSP40 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; C087041:MDJ1 protein, S cerevisiae; C086039:MGE1 protein, S cerevisiae; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D033681:Mitochondrial Membrane Transport Proteins; D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; D008156:Luciferases