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Proc Natl Acad Sci U S A. Jul 5, 1994; 91(14): 6481–6485.

A role for a eukaryotic GrpE-related protein, Mge1p, in protein translocation.


The 70-kDa heat shock proteins (hsp70s) function as molecular chaperones in a wide variety of cellular processes through cycles of binding and release from substrate proteins coupled to cycles of ATP hydrolysis. In the prokaryote Escherichia coli, the hsp70 DnaK functions with two other proteins, DnaJ and GrpE, which modulate the activity of DnaK. While numerous hsp70s and DnaJ-related proteins have been identified in eukaryotes, to our knowledge no GrpE-related proteins have been reported. We report the isolation and characterization of a eukaryotic grpE-related gene, MGE1. MGE1, an essential nuclear gene of the yeast Saccharomyces cerevisiae, encodes a soluble protein of the mitochondrial matrix. Cells with reduced expression of Mge1p accumulate the precursor form of a mitochondrial protein. Since mitochondrial hsp70 is required for translocation of precursors of mitochondrial proteins from the cytosol into the matrix of mitochondria, these data suggest that Mge1p acts in concert with mitochondrial hsp70 in protein translocation.

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  • Craig EA, Gambill BD, Nelson RJ. Heat shock proteins: molecular chaperones of protein biogenesis. Microbiol Rev. 1993 Jun;57(2):402–414. [PMC free article] [PubMed]
  • Hartl FU, Hlodan R, Langer T. Molecular chaperones in protein folding: the art of avoiding sticky situations. Trends Biochem Sci. 1994 Jan;19(1):20–25. [PubMed]
  • Langer T, Lu C, Echols H, Flanagan J, Hayer MK, Hartl FU. Successive action of DnaK, DnaJ and GroEL along the pathway of chaperone-mediated protein folding. Nature. 1992 Apr 23;356(6371):683–689. [PubMed]
  • Schröder H, Langer T, Hartl FU, Bukau B. DnaK, DnaJ and GrpE form a cellular chaperone machinery capable of repairing heat-induced protein damage. EMBO J. 1993 Nov;12(11):4137–4144. [PMC free article] [PubMed]
  • Liberek K, Skowyra D, Zylicz M, Johnson C, Georgopoulos C. The Escherichia coli DnaK chaperone, the 70-kDa heat shock protein eukaryotic equivalent, changes conformation upon ATP hydrolysis, thus triggering its dissociation from a bound target protein. J Biol Chem. 1991 Aug 5;266(22):14491–14496. [PubMed]
  • Straus DB, Walter WA, Gross CA. Escherichia coli heat shock gene mutants are defective in proteolysis. Genes Dev. 1988 Dec;2(12B):1851–1858. [PubMed]
  • Straus D, Walter W, Gross CA. DnaK, DnaJ, and GrpE heat shock proteins negatively regulate heat shock gene expression by controlling the synthesis and stability of sigma 32. Genes Dev. 1990 Dec;4(12A):2202–2209. [PubMed]
  • Wild J, Altman E, Yura T, Gross CA. DnaK and DnaJ heat shock proteins participate in protein export in Escherichia coli. Genes Dev. 1992 Jul;6(7):1165–1172. [PubMed]
  • Craig EA, Kramer J, Shilling J, Werner-Washburne M, Holmes S, Kosic-Smithers J, Nicolet CM. SSC1, an essential member of the yeast HSP70 multigene family, encodes a mitochondrial protein. Mol Cell Biol. 1989 Jul;9(7):3000–3008. [PMC free article] [PubMed]
  • Stuart RA, Cyr DM, Craig EA, Neupert W. Mitochondrial molecular chaperones: their role in protein translocation. Trends Biochem Sci. 1994 Feb;19(2):87–92. [PubMed]
  • Kang PJ, Ostermann J, Shilling J, Neupert W, Craig EA, Pfanner N. Requirement for hsp70 in the mitochondrial matrix for translocation and folding of precursor proteins. Nature. 1990 Nov 8;348(6297):137–143. [PubMed]
  • Ostermann J, Voos W, Kang PJ, Craig EA, Neupert W, Pfanner N. Precursor proteins in transit through mitochondrial contact sites interact with hsp70 in the matrix. FEBS Lett. 1990 Dec 17;277(1-2):281–284. [PubMed]
  • Scherer PE, Krieg UC, Hwang ST, Vestweber D, Schatz G. A precursor protein partly translocated into yeast mitochondria is bound to a 70 kd mitochondrial stress protein. EMBO J. 1990 Dec;9(13):4315–4322. [PMC free article] [PubMed]
  • Sikorski RS, Hieter P. A system of shuttle vectors and yeast host strains designed for efficient manipulation of DNA in Saccharomyces cerevisiae. Genetics. 1989 May;122(1):19–27. [PMC free article] [PubMed]
  • Gambill BD, Voos W, Kang PJ, Miao B, Langer T, Craig EA, Pfanner N. A dual role for mitochondrial heat shock protein 70 in membrane translocation of preproteins. J Cell Biol. 1993 Oct;123(1):109–117. [PMC free article] [PubMed]
  • Rassow J, Guiard B, Wienhues U, Herzog V, Hartl FU, Neupert W. Translocation arrest by reversible folding of a precursor protein imported into mitochondria. A means to quantitate translocation contact sites. J Cell Biol. 1989 Oct;109(4 Pt 1):1421–1428. [PMC free article] [PubMed]
  • Pfanner N, Tropschug M, Neupert W. Mitochondrial protein import: nucleoside triphosphates are involved in conferring import-competence to precursors. Cell. 1987 Jun 19;49(6):815–823. [PubMed]
  • Söllner T, Rassow J, Pfanner N. Analysis of mitochondrial protein import using translocation intermediates and specific antibodies. Methods Cell Biol. 1991;34:345–358. [PubMed]
  • Kambouris NG, Burke DJ, Creutz CE. Cloning and genetic analysis of the gene encoding a new protein kinase in Saccharomyces cerevisiae. Yeast. 1993 Feb;9(2):141–150. [PubMed]
  • Lipinska B, King J, Ang D, Georgopoulos C. Sequence analysis and transcriptional regulation of the Escherichia coli grpE gene, encoding a heat shock protein. Nucleic Acids Res. 1988 Aug 11;16(15):7545–7562. [PMC free article] [PubMed]
  • Douglas MG, McCammon MT, Vassarotti A. Targeting proteins into mitochondria. Microbiol Rev. 1986 Jun;50(2):166–178. [PMC free article] [PubMed]
  • Johnson C, Chandrasekhar GN, Georgopoulos C. Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro. J Bacteriol. 1989 Mar;171(3):1590–1596. [PMC free article] [PubMed]
  • Johnston M. A model fungal gene regulatory mechanism: the GAL genes of Saccharomyces cerevisiae. Microbiol Rev. 1987 Dec;51(4):458–476. [PMC free article] [PubMed]
  • Ang D, Georgopoulos C. The heat-shock-regulated grpE gene of Escherichia coli is required for bacterial growth at all temperatures but is dispensable in certain mutant backgrounds. J Bacteriol. 1989 May;171(5):2748–2755. [PMC free article] [PubMed]
  • Zylicz M, Ang D, Georgopoulos C. The grpE protein of Escherichia coli. Purification and properties. J Biol Chem. 1987 Dec 25;262(36):17437–17442. [PubMed]
  • Osipiuk J, Georgopoulos C, Zylicz M. Initiation of lambda DNA replication. The Escherichia coli small heat shock proteins, DnaJ and GrpE, increase DnaK's affinity for the lambda P protein. J Biol Chem. 1993 Mar 5;268(7):4821–4827. [PubMed]
  • Liberek K, Marszalek J, Ang D, Georgopoulos C, Zylicz M. Escherichia coli DnaJ and GrpE heat shock proteins jointly stimulate ATPase activity of DnaK. Proc Natl Acad Sci U S A. 1991 Apr 1;88(7):2874–2878. [PMC free article] [PubMed]

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