Abstract
The yeast mitochondrial outer membrane contains a major 70 kd protein with an amino-terminal hydrophobic membrane anchor and a hydrophilic 60 kd domain exposed to the cytosol. We now show that this protein (which we term MAS70) accelerates the mitochondrial import of many (but not all) precursor proteins. Anti-MAS70 IgGs or removal of MAS70 from the mitochondria by either mild trypsin treatment or by disrupting the nuclear MAS70 gene inhibits import of the F1-ATPase beta-subunit, the ADP/ATP translocator, and of several other precursors into isolated mitochondria by up to 75%, but has little effect on the import of porin. Intact cells of a mas70 null mutant import the F1-ATPase alpha-subunit and beta-subunits, cytochrome c1 and other precursors at least several fold more slowly than wild-type cells. Removal of MAS70 from wild-type mitochondria inhibits binding of the ADP/ATP translocator to the mitochondrial surface, indicating that MAS70 mediates one of the earliest import steps. Several precursors are thus imported by a pathway in which MAS70 functions as a receptor-like component. MAS70 is not essential for import of these precursors, but only accelerates this process.
Full text
PDFImages in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cheng M. Y., Hartl F. U., Martin J., Pollock R. A., Kalousek F., Neupert W., Hallberg E. M., Hallberg R. L., Horwich A. L. Mitochondrial heat-shock protein hsp60 is essential for assembly of proteins imported into yeast mitochondria. Nature. 1989 Feb 16;337(6208):620–625. doi: 10.1038/337620a0. [DOI] [PubMed] [Google Scholar]
- Daum G., Böhni P. C., Schatz G. Import of proteins into mitochondria. Cytochrome b2 and cytochrome c peroxidase are located in the intermembrane space of yeast mitochondria. J Biol Chem. 1982 Nov 10;257(21):13028–13033. [PubMed] [Google Scholar]
- Deshaies R. J., Koch B. D., Werner-Washburne M., Craig E. A., Schekman R. A subfamily of stress proteins facilitates translocation of secretory and mitochondrial precursor polypeptides. Nature. 1988 Apr 28;332(6167):800–805. doi: 10.1038/332800a0. [DOI] [PubMed] [Google Scholar]
- Eilers M., Schatz G. Binding of a specific ligand inhibits import of a purified precursor protein into mitochondria. Nature. 1986 Jul 17;322(6076):228–232. doi: 10.1038/322228a0. [DOI] [PubMed] [Google Scholar]
- Ey P. L., Prowse S. J., Jenkin C. R. Isolation of pure IgG1, IgG2a and IgG2b immunoglobulins from mouse serum using protein A-sepharose. Immunochemistry. 1978 Jul;15(7):429–436. doi: 10.1016/0161-5890(78)90070-6. [DOI] [PubMed] [Google Scholar]
- Griffiths G., Matteoni R., Back R., Hoflack B. Characterization of the cation-independent mannose 6-phosphate receptor-enriched prelysosomal compartment in NRK cells. J Cell Sci. 1990 Mar;95(Pt 3):441–461. doi: 10.1242/jcs.95.3.441. [DOI] [PubMed] [Google Scholar]
- Griffiths G., McDowall A., Back R., Dubochet J. On the preparation of cryosections for immunocytochemistry. J Ultrastruct Res. 1984 Oct;89(1):65–78. doi: 10.1016/s0022-5320(84)80024-6. [DOI] [PubMed] [Google Scholar]
- Griffiths G., Simons K., Warren G., Tokuyasu K. T. Immunoelectron microscopy using thin, frozen sections: application to studies of the intracellular transport of Semliki Forest virus spike glycoproteins. Methods Enzymol. 1983;96:466–485. doi: 10.1016/s0076-6879(83)96041-x. [DOI] [PubMed] [Google Scholar]
- Haid A., Suissa M. Immunochemical identification of membrane proteins after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Methods Enzymol. 1983;96:192–205. doi: 10.1016/s0076-6879(83)96017-2. [DOI] [PubMed] [Google Scholar]
- Hartl F. U., Neupert W. Protein sorting to mitochondria: evolutionary conservations of folding and assembly. Science. 1990 Feb 23;247(4945):930–938. doi: 10.1126/science.2406905. [DOI] [PubMed] [Google Scholar]
- Hase T., Müller U., Riezman H., Schatz G. A 70-kd protein of the yeast mitochondrial outer membrane is targeted and anchored via its extreme amino terminus. EMBO J. 1984 Dec 20;3(13):3157–3164. doi: 10.1002/j.1460-2075.1984.tb02274.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 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. 1983;2(12):2169–2172. doi: 10.1002/j.1460-2075.1983.tb01718.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hawlitschek G., Schneider H., Schmidt B., Tropschug M., Hartl F. U., Neupert W. Mitochondrial protein import: identification of processing peptidase and of PEP, a processing enhancing protein. Cell. 1988 Jun 3;53(5):795–806. doi: 10.1016/0092-8674(88)90096-7. [DOI] [PubMed] [Google Scholar]
- Hurt E. C., Pesold-Hurt B., Schatz G. The amino-terminal region of an imported mitochondrial precursor polypeptide can direct cytoplasmic dihydrofolate reductase into the mitochondrial matrix. EMBO J. 1984 Dec 20;3(13):3149–3156. doi: 10.1002/j.1460-2075.1984.tb02272.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kozłowski M., Zagórski W. Stable preparation of yeast mitochondria and mitoplasts synthesizing specific polypeptides. Anal Biochem. 1988 Aug 1;172(2):382–391. doi: 10.1016/0003-2697(88)90459-9. [DOI] [PubMed] [Google Scholar]
- Melton D. A., Krieg P. A., Rebagliati M. R., Maniatis T., Zinn K., Green M. R. Efficient in vitro synthesis of biologically active RNA and RNA hybridization probes from plasmids containing a bacteriophage SP6 promoter. Nucleic Acids Res. 1984 Sep 25;12(18):7035–7056. doi: 10.1093/nar/12.18.7035. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Murakami H., Pain D., Blobel G. 70-kD heat shock-related protein is one of at least two distinct cytosolic factors stimulating protein import into mitochondria. J Cell Biol. 1988 Dec;107(6 Pt 1):2051–2057. doi: 10.1083/jcb.107.6.2051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ohba M., Schatz G. Protein import into yeast mitochondria is inhibited by antibodies raised against 45-kd proteins of the outer membrane. EMBO J. 1987 Jul;6(7):2109–2115. doi: 10.1002/j.1460-2075.1987.tb02477.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ou W. J., Ito A., Okazaki H., Omura T. Purification and characterization of a processing protease from rat liver mitochondria. EMBO J. 1989 Sep;8(9):2605–2612. doi: 10.1002/j.1460-2075.1989.tb08400.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Pfanner N., Neupert W. Distinct steps in the import of ADP/ATP carrier into mitochondria. J Biol Chem. 1987 Jun 5;262(16):7528–7536. [PubMed] [Google Scholar]
- 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. doi: 10.1016/0092-8674(87)90619-2. [DOI] [PubMed] [Google Scholar]
- Reid G. A., Schatz G. Import of proteins into mitochondria. Extramitochondrial pools and post-translational import of mitochondrial protein precursors in vivo. J Biol Chem. 1982 Nov 10;257(21):13062–13067. [PubMed] [Google Scholar]
- Riezman H., Hase T., van Loon A. P., Grivell L. A., Suda K., Schatz G. Import of proteins into mitochondria: a 70 kilodalton outer membrane protein with a large carboxy-terminal deletion is still transported to the outer membrane. EMBO J. 1983;2(12):2161–2168. doi: 10.1002/j.1460-2075.1983.tb01717.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Riezman H., Hay R., Gasser S., Daum G., Schneider G., Witte C., Schatz G. The outer membrane of yeast mitochondria: isolation of outside-out sealed vesicles. EMBO J. 1983;2(7):1105–1111. doi: 10.1002/j.1460-2075.1983.tb01553.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Riezman H., Hay R., Witte C., Nelson N., Schatz G. Yeast mitochondrial outer membrane specifically binds cytoplasmically-synthesized precursors of mitochondrial proteins. EMBO J. 1983;2(7):1113–1118. doi: 10.1002/j.1460-2075.1983.tb01554.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sikorski R. S., Boguski M. S., Goebl M., Hieter P. A repeating amino acid motif in CDC23 defines a family of proteins and a new relationship among genes required for mitosis and RNA synthesis. Cell. 1990 Jan 26;60(2):307–317. doi: 10.1016/0092-8674(90)90745-z. [DOI] [PubMed] [Google Scholar]
- Smagula C., Douglas M. G. Mitochondrial import of the ADP/ATP carrier protein in Saccharomyces cerevisiae. Sequences required for receptor binding and membrane translocation. J Biol Chem. 1988 May 15;263(14):6783–6790. [PubMed] [Google Scholar]
- Stueber D., Ibrahimi I., Cutler D., Dobberstein B., Bujard H. A novel in vitro transcription-translation system: accurate and efficient synthesis of single proteins from cloned DNA sequences. EMBO J. 1984 Dec 20;3(13):3143–3148. doi: 10.1002/j.1460-2075.1984.tb02271.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Söllner T., Griffiths G., Pfaller R., Pfanner N., Neupert W. MOM19, an import receptor for mitochondrial precursor proteins. Cell. 1989 Dec 22;59(6):1061–1070. doi: 10.1016/0092-8674(89)90762-9. [DOI] [PubMed] [Google Scholar]
- Verner K., Schatz G. Protein translocation across membranes. Science. 1988 Sep 9;241(4871):1307–1313. doi: 10.1126/science.2842866. [DOI] [PubMed] [Google Scholar]
- Vestweber D., Brunner J., Baker A., Schatz G. A 42K outer-membrane protein is a component of the yeast mitochondrial protein import site. Nature. 1989 Sep 21;341(6239):205–209. doi: 10.1038/341205a0. [DOI] [PubMed] [Google Scholar]
- Yaffe M. P., Schatz G. Two nuclear mutations that block mitochondrial protein import in yeast. Proc Natl Acad Sci U S A. 1984 Aug;81(15):4819–4823. doi: 10.1073/pnas.81.15.4819. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Yang M., Jensen R. E., Yaffe M. P., Oppliger W., Schatz G. Import of proteins into yeast mitochondria: the purified matrix processing protease contains two subunits which are encoded by the nuclear MAS1 and MAS2 genes. EMBO J. 1988 Dec 1;7(12):3857–3862. doi: 10.1002/j.1460-2075.1988.tb03271.x. [DOI] [PMC free article] [PubMed] [Google Scholar]