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Mitochondrial protein import: modification of sulfhydryl groups of the inner mitochondrial membrane import machinery in Solanum tuberosum inhibits protein import

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Abstract

Protein import into mitochondria involves several components of the mitochondrial outer and inner membranes as well as molecular chaperones located inside mitochondria. Here, we have investigated the effect of sulfhydryl group reagents on import of the in vitro transcribed/translated precursor of the F1β subunit of the ATP synthase (pF1β) into Solanum tuberosum mitochondria. We have used a reducing agent, dithiothreitol (DTT), a membrane-permeant alkylating agent, N-ethylmaleimide (NEM), a non-permeant alkylating agent, 3-(N-maleimidopropionyl)biocytin (MPB), an SH-group specific agent and cross-linker 5,5′-dithiobis-(2-nitrobenzoic acid) (DTNB) as well as an oxidizing cross-linker, copper sulfate. DTT stimulated the mitochondrial protein import, whereas NEM, MPB, DTNB and Cu2+ were inhibitory. Inhibition by Cu2+ could be reversed by addition of DTT. The efficiency of inhibition was higher in energized mitochondria than in non-energized. We have dissected the effect of the SH-group reagents on binding, unfolding and transport of the precursor into mitochondria. Our results demonstrated that the inhibitory effect of NEM, DTNB and Cu2+ on the efficiency of import was not due to the interaction of the SH-group reagents with import receptors. Modification of pF1β with NEM prior to the import resulted in stimulation of import, whereas DTNB and Cu2+ were inhibitory. NEM, MPB, DTNB and Cu2+ inhibited import of the NEM-modified pF1β into intact mitochondria. Import of pF1β through a receptor-independent bypass-route as well as import into mitoplasts were sensitive to DTT, NEM, MPB, DTNB and Cu2+ in a similar manner as import into mitochondria. As MPB does not cross the inner membrane, these results indicated that redox and conformational status of SH groups located on the outer surface of the inner mitochondrial membrane were essential for protein import.

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References

  1. Abrahams JP, Leslie AG, Lutter R, Walker J: Structure at 2.8 Å resolution of F1-ATPase from bovine heart mitochondria. Nature 370: 621–628 (1994).

    Google Scholar 

  2. Baker KP, Schaniel A, Vestweber D, Schatz G: A yeast mitochondrial outer membrane protein essential for protein import and cell viability. Nature 348: 605–609 (1990).

    Google Scholar 

  3. Becker K, Guiard B, Rassow J, Sollner T, Pfanner N: Targeting of a chemically pure preprotein to mitochondria does not require the addition of a cytosolic signal recognition factor. J Biol Chem 267: 5637–5643 (1992).

    Google Scholar 

  4. Berthold J, Bauer MF, Schneider H-C, Klaus C, Dietmeier K, Neupert W, Brunner M:The MIM complexmediates preprotein translocation across the mitochondrial inner membrane and couples it to the mt-Hsp70/ATP driving system. Cell 81: 1085– 1093 (1995).

    Google Scholar 

  5. Blom J: The protein import system of the yeast mitochondrial inner membrane. Ph.D. thesis, University of Amsterdam, Amsterdam (1995).

    Google Scholar 

  6. Blom J, Dekker PJT, Meijer M: Functional and physical interactions of components of the yeast mitochondrial innermembrane importmachinery (MIM). Eur J Biochem 232: 309– 314 (1995).

    Google Scholar 

  7. Boutry M, Chua N-H: A nuclear gene encoding the beta subunit of the mitochondrial ATP synthase complex in Nicotiana plumbaginifolia. EMBO J. 4: 2159–2165 (1985).

    Google Scholar 

  8. Bradford MM: A rapid and sensitive method for the quantitation of microgram quantities of protein utilizing the principle of protein-dye binding. Anal Biochem 72: 248–254 (1976).

    Google Scholar 

  9. Bömer U, Rassow J, Zufall N, Pfanner N, Meijer M, Maarse AC: The preprotein translocase of the inner mitochondrial membrane: evolutionary conservation of targeting and assembly of Tim17. J Mol Biol 262: 389–395 (1996).

    Google Scholar 

  10. Chen W-J, Douglas MG: The role of protein structure in the mitochondrial import pathway. J BiolChem 262: 15605–15609 (1987).

    Google Scholar 

  11. Dekker PJT, Keil P, Rassow J, Maarse AC, Pfanner N, Meijer M: Identification of MIM23, a putative component of the protein import machinery of the mitochondrial inner membrane. FEBS Lett 330: 66–70 (1993).

    Google Scholar 

  12. Douce R: Mitochondria in Higher Plants. Structure, Function and Biogenesis, pp. 23–25. Academic Press, London (1985).

    Google Scholar 

  13. Emtage JLT, Jensen RE: MAS6 encodes an essential inner membrane component of the yeast mitochondrial protein import pathway. J Cell Biol 122: 1003–1012 (1993).

    Google Scholar 

  14. Eriksson AC, Sjöling S, Glaser E: Characterization of the bifunctional mitochondrial processing peptidase (MPP)/bc1 complex in Spinacia oleracea. J Bioenerg Biomembr 28: 283– 290 (1996).

    Google Scholar 

  15. Friedman AL, Keegstra K: Chloroplast protein import. Quantitative analysis of precursor binding. Plant Physiol 89: 993–999 (1989).

    Google Scholar 

  16. Glaser E, Knorpp C, Hugosson M, von Stedingk E: Macromolecular movement into mitochondria. Meth Cell Biol 50: 269–281 (1995).

    Google Scholar 

  17. Glaser E, Sjöling S, Szigyarto C, Eriksson AC: Mitochondrial protein import: precursor processing is catalysed by the integrated mitochondrial processing peptidase (MPP)/bc1 complex and degradation by the ATP-dependent proteinase. Biochim Biophys Acta 1275: 33–37 (1996).

    Google Scholar 

  18. Glick BS: Can Hsp70 proteins act as force-generating motors? Cell 80: 11–14 (1995).

    Google Scholar 

  19. Gratzer S, Lithgow T, Bauer RE, Lamping E, Paltauf F, Kohlwein SD, Haucke V, Junne T, Schatz G, Horst M: Mas37p, a novel receptor subunit for protein import into mitochondria. J Cell Biol 129: 25–34 (1995).

    Google Scholar 

  20. Hachiya N, Alam R, Sakasegawa Y, Sakaguchi M, Mihara K, Omura T: A mitochondrial import factor purified from rat liver cytosol is an ATP-dependent conformational modulator for precursor proteins. EMBO J 12: 1579–1586 (1993).

    Google Scholar 

  21. Hachiya N, Komiya T, Alam R, Iwahashi J, Sakaguchi M, Omura T, Mihara K: MSF, a novel cytoplasmic chaperone which functions in precursor targeting tomitochondria. EMBO J 13: 5146–5154 (1994).

    Google Scholar 

  22. Hachiya N, Mihara K, Suda K, Horst M, Schatz G, Lithgow T: Reconstitution of the initial steps of mitochondrial protein import. Nature 376: 705–709 (1995).

    Google Scholar 

  23. Hartl F-U, Hlodan R, Langer T: Molecular chaperones in protein folding: the art of avoiding sticky situations. Trends Biochem Sci 19: 20–25 (1994).

    Google Scholar 

  24. Hase T, Riezman H, Suda K, Schatz G: Import of proteins into mitochondria: nucleotide sequence of the gene for a 70-kd protein of the yeast mitochondrial outer membrane. EMBO J 2: 2169–2172 (1983).

    Google Scholar 

  25. Hatase O, Tsutsui K, Oda T: Mitochondrial sulfhydryl groups. A possible endogenous probe of conformational changes in the mitochondrial membrane. J Biochem 82: 359–363 (1977).

    Google Scholar 

  26. Haucke V, Lithgow T, Rospert S, Hahne K, Schatz G: The yeast mitochondrial protein import receptor mas20p binds precursor proteins through electrostatic interaction with a positively charged presequence. J Biol Chem 270: 5565–5570 (1995).

    Google Scholar 

  27. Heins L, Schmitz UK: A receptor for protein import into potato mitochondria. Plant J 9: 829–839 (1996).

    Google Scholar 

  28. Kanamori T, Nishikawa S-I, Shin I, Schulz P, Endo T: Probing the environment along the protein import pathways in yeast mitochondria by site-specific photocrosslinking. Proc Nat Acad Sci USA 94: 485–490 (1997).

    Google Scholar 

  29. Knorpp C, Hugosson M, Sjöling S, Eriksson AC, Glaser E: Tissue-specific differences of the mitochondrial protein import machinery: in vitro import, processing and degradation of the pre-F1β subunit of the ATP synthase in spinach leaf and root mitochondria. Plant Mol Biol 26: 571–579 (1994).

    Google Scholar 

  30. Kronidou NG, Oppliger W, Bolliger L, Hannavy K, Glick BS, Schatz G, Horst M: Dynamic interaction between Isp45 and mitochondrial Hsp70 in the protein import system of the yeast mitochondrial inner membrane. Proc Natl Acad Sci USA 91: 12818–12822 (1994).

    Google Scholar 

  31. Kyte J, Doolittle RF:A simple method for displaying the hydropathic character of a protein. J Mol Biol 157: 105–132 (1982).

    Google Scholar 

  32. Laemmli UK: Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227: 680– 685 (1970).

    Google Scholar 

  33. Lill R, Neupert W: Mechanisms of protein import across the mitochondrial outer membrane. Trends Cell Biol 6: 56–61 (1996).

    Google Scholar 

  34. Lithgow T, Glick BS, Schatz G: The protein import receptor of mitochondria. Trends Biochem Sci 20: 98–101 (1995).

    Google Scholar 

  35. Lithgow T, Junne T, Suda K, Gratzer S, Schatz G: The mitochondrial outer membrane protein mas22p is essential for protein import and viability of yeast. Proc Natl Acad Sci USA 91: 11973–11977 (1994).

    Google Scholar 

  36. Maarse AC, Blom J, Grivell LA, Meijer M: MPI1, an essential gene encoding a mitochondrial membrane protein, is possibly involved in protein import into yeast mitochondria. EMBO J 11: 3619–3628 (1992).

    Google Scholar 

  37. Maarse AC, Blom J, Keil P, Pfanner N, Meijer M: Identification of the essential yeast protein MIM17, an integral mitochondrial inner membrane protein involved in protein import. FEBS Lett 349: 215–221 (1994).

    Google Scholar 

  38. Mayer A, Nargang FE, Neupert W, Lill R: MOM22 is a receptor for mitochondrial targeting sequences and cooperates with MOM19. EMBO J 14: 4204–4211 (1995).

    Google Scholar 

  39. Meister A: Glutathione metabolism and its selective modification. J Biol Chem 263: 17205–17208 (1988).

    Google Scholar 

  40. Ohba M, Schatz G: Disruption of the outer membrane restores protein import to trypsin-treated yeast mitochondria. EMBO J 6: 2117–2122 (1987).

    Google Scholar 

  41. Pfaller R, Steger HF, Rassow J, Pfanner N, Neupert W: Import pathways of precursor proteins into mitochondria: multiple receptor sites are followed by a common membrane insertion site. J Cell Biol 107: 2483–2490 (1988).

    Google Scholar 

  42. Pfanner N, Craig EA, Meijer M: The protein import machinery of the mitochondrial inner membrane. Trends Biochem Sci 19: 368–372 (1994).

    Google Scholar 

  43. Pfanner N, Meijer M: Pulling in the proteins. Curr Biol 5: 132–135 (1995).

    Google Scholar 

  44. Pical C, Fredlund KM, Petit PX, Sommarin M, Møller IM: The outer membrane of plant mitochondria contains a calciumdependent protein kinase and multiple phosphoproteins. FEBS Lett 336: 347–351 (1993).

    Google Scholar 

  45. Pilon M, de Kruijff B, Weisbeek PJ: New insights into the import mechanism of the ferredoxin precursor into chloroplasts. J Biol Chem 267: 2548–2556 (1992).

    Google Scholar 

  46. Schneider H-K, Westerman B, Neupert W, Brunner M: The nucleotide exchange factor MGE exerts a key function in the ATP-dependent cycle of mtHsp70-TIM44 interaction driving mitochondrial protein import. EMBO J 21: 5796–5803 (1996).

    Google Scholar 

  47. Schwaiger M, Herzog V, Neupert W: Characterization of translocation contact sites involved in the import of mitochondrial proteins. J Cell Biol 105: 235–246 (1987).

    Google Scholar 

  48. Seedorf M, Soll J: Copper chloride, an inhibitor of protein import into chloroplasts. FEBS Lett. 367: 19–22 (1995).

    Google Scholar 

  49. Sheffield WP, Shore GC, Randall SK: Effects of 70-kilodalton heat shock protein on polypeptide folding, aggregation, and import competence. J Biol Chem 19: 11069–11076 (1990).

    Google Scholar 

  50. Sirrenberg C, Bauer MF, Guiard B, Neupert W, Brunner M.: Import of carrier proteins into the mitochondrial inner membrane mediated by TIM22. Nature 384: 582–585 (1996).

    Google Scholar 

  51. Soll J: New insights into the protein import machinery of the chloroplast's outer envelope. Bot Acta 108: 277–282 (1995).

    Google Scholar 

  52. Stuart RA, Cyr DM, Craig EA, Neupert W: Mitochondrial molecular chaperones: their role in protein translocation. Trends Biochem Sci 19: 87–92 (1994).

    Google Scholar 

  53. Tokatlidis K, Junne T, Moes S, Schatz G, Glick B, Kronidou N: Translocation arrest of an intramitochondrial sorting signal next to TIM11 at the inner membrane import site. Nature 384: 585–588 (1996).

    Google Scholar 

  54. Ungermann C, Neupert W, Cyr DM: The role of hsp70 in conferring unidirectionality on protein translocation into mitochondria. Science 226: 1250–1253 (1994).

    Google Scholar 

  55. Wachter C, Schatz G, Glick BS: Protein import into mitochondria: The requirement for external ATP is precursorspecific whereas intramitochondrial ATP is universally needed for translocation into the matrix. Mol Biol Cell 5: 465–474 (1994).

    Google Scholar 

  56. Wagner I, Arlt H, van Dyck L, Langer T, Neupert W: Molecular chaperones cooperate with PIM1 protease in the degradation of misfolded proteins in mitochondria. EMBO J 13: 5135–5145 (1994).

    Google Scholar 

  57. Watts FZ, Walters AJ, Moore AL: Characterisation of PHPS1, a cDNAencoding amitochondrial HSP70 from Pisumsativum. Plant Mol Biol 18: 23–32 (1992).

    Google Scholar 

  58. Whelan J, Knorpp C, Glaser E: Sorting of precursor proteins between isolated spinach leaf mitochondria and chloroplasts. Plant Mol Biol 14: 977–982 (1990).

    Google Scholar 

  59. Zhen R-G, Kim EJ, Rea PA: Localization of cytosolically oriented maleimide-reactive domain of vacuolar H+-pyrophosphatase. J Biol Chem 269: 23342–23350 (1994).

    Google Scholar 

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von Stedingk, E.M., Pavlov, P.F., Grinkevich, V.A. et al. Mitochondrial protein import: modification of sulfhydryl groups of the inner mitochondrial membrane import machinery in Solanum tuberosum inhibits protein import. Plant Mol Biol 35, 809–820 (1997). https://doi.org/10.1023/A:1005838028160

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