A crucial role of the mitochondrial protein import receptor MOM19 for the biogenesis of mitochondria (original) (raw)
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Protein import into mitochondria of Neurospora crassa
Fungal Genetics and Biology, 2002
Biogenesis of mitochondria requires import of several hundreds of different nuclear-encoded preproteins needed for mitochondrial structure and function. Import and sorting of these preproteins is a multistep process facilitated by complex proteinaceous machineries located in the mitochondrial outer and inner membranes. The translocase of the mitochondrial outer membrane, the TOM complex, comprises receptors which specifically recognize mitochondrial preproteins and a protein conducting channel formed by TOM40. The TOM complex is able to insert resident proteins into the outer membrane and to translocate proteins into the intermembrane space. For import of inner membrane or matrix proteins, the TOM complex cooperates with translocases of the inner membrane, the TIM complexes. During the past 30 years, intense research on fungi enabled the identification and mechanistic characterization of a number of different proteins involved in protein translocation. This review focuses on the contributions of the filamentous fungus Neurospora crassa to our current understanding of mitochondrial protein import, with special emphasis on the structure and function of the TOM complex. Ó
Biochemical Journal, 1993
We have cloned and sequenced a cDNA encoding a 17.8 kDa subunit of the hydrophobic fragment of complex I from Neurospora crassa. The deduced primary structure of this subunit was partially confirmed by automated Edman degradation of the isolated polypeptide. The sequence data obtained indicate that the 17.8 kDa subunit is made as an extended precursor of 20.8 kDa. Resistance of the polypeptide to alkaline extraction from mitochondrial membranes and the existence of a putative membrane-spanning domain suggests that the 17.8 kDa subunit is an intrinsic (bitopic) membrane protein. The in vitro synthesized precursor of the 17.8 kDa subunit can be efficiently imported into isolated mitochondria, where it is cleaved to the mature species by the metal-dependent matrix-processing peptidase. The in vitro imported mature subunit is found mainly exposed to the mitochondrial intermembrane space. However, a significant fraction of the imported polypeptide acquires the same membrane topology as t...
[26] Biosynthesis and assembly of nuclear-coded mitochondrial membrane proteins in Neurospora crassa
Biomembranes Part K: Membrane Biogenesis: Assembly and Targeting (Prokaryotes, Mitochondria, and Chloroplasts), 1983
Section I. Prokaryotic Membranes A. General Methods 1. Genetic Analysis of Protein Export in Escherichia JONATHAN BECKWITH AND coli THOMAS J. SILHAVY 3 2. Isolation and Characterization of Mutants of Esche-THOMAS J. SILHAVY AND richia coli Kl2 Affected in Protein Localization JONATHAN BECKWITH 3. Purification and Characterization of Leader Pepti-P. B. WOLFE, C. ZWIZINSKI, dase from Escherichia coli AND WILLIAM WICKNER 40 4. Molecular Genetics of Escherichia coli Leader Pep-TAKAYASU DATE, tidase PAMELA SILVER, AND WILLIAM WICKNER 5. Pulse-Labeling Studies of Membrane Assembly and WILLIAM WICKNER, Protein Secretion in Intact Cells: M13 Coat Pro-TAKAYASU DATE, tein RICHARD ZIMMERMANN, AND KOREAKI ITO 57 6. Synthesis of Proteins by Membrane-Associated PNANG C. TAI, Polysomes and Free Polysomes MICHAEL P. CAULFIELD, AND BERNARD D. DAVIS 62 7. Preparation of Free and Membrane-Bound Poly-LINDA L. RANDALL AND somes from Escherichia coli SIMON J. S. HARDY 70 8. Analysis of Cotranslational Proteolytic Processing of LARS-GÖRAN JOSEFSSON Nascent Chains Using Two-Dimensional Gel AND LINDA L. RANDALL Electrophoresis B. Outer Membrane 9. Proteins Forming Large Channels from Bacterial HIROSHI NIKAIDO and Mitochondrial Outer Membranes: Porins and Phage Lambda Receptor Protein 10. Phage λ Receptor (LamB Protein) in Escherichia coli MAXIME SCHWARTZ 11. Synthesis and Assembly of the Outer Membrane IAN CROWLESMITH AND Proteins OmpA and OmpF of Escherichia coli KONRAD GAMON 12. Isolation of Mutants of the Major Outer Membrane JACK COLEMAN, Lipoprotein of Escherichia coli for the Study of Its SUMIKO INOUYE, Assembly AND ΜASAYORI INOUYE ν VI TABLE OF CONTENTS C. Inner Membrane 13. Analysis of Μ13 Procoat Assembly into Membranes COLIN WATTS, in Vitro JOEL M. GOODMAN, PAMELA SILVER, AND WILLIAM WICKNER 14. Insertion of Proteins into Bacterial Membranes PETER MODEL AND MARJORIE RUSSEL 15. Influence of Membrane Potential on the Insertion ROBERT C. LANDICK, and Transport of Proteins in Bacterial Membranes CHARLES J. DANIELS, AND DALE L. OXENDER 16. Penicillinase Secretion in Vivo and in Vitro JENNIFER Β. K. NIELSEN 17. Lactose Permease of Escherichia coli J. K. WRIGHT, R. M. TEATHER, AND P.OVERATH 18. Cloning of the Structural Genes of the Escherichia DAVID A. JANS AND coli Adenosinetriphosphatase Complex FRANK GIBSON 19. Biogenesis of an Oligomeric Membrane Protein WILLIAM S. A. BRUSILOW, Complex: The Proton Translocating ATPase of ROBERT P. GUNSALUS, AND Escherichia coli ROBERT D. SIMONI 20. Analysis of Escherichia coli ATP Synthase Subunits JOHN E. WALKER AND by DNA and Protein Sequencing NICHOLAS J. GAY 21. Biogenesis of Purple Membrane in Halobacteria DOROTHEA-CH. NEUGEBAUER, HORST-PETER ZINGSHEIM, AND DIETER OESTERHELT 22. Isolation of the Bacterioopsin Gene by Colony Hy-HEIKE VOGELSANG, bridization WOLFGANG OERTEL, AND DIETER OESTERHELT Section II. Mitochondria 23. Assessing Import of Proteins into Mitochondria: An SUSAN M. GASSER AND Overview RICK HAY 245 24. Molecular Cloning of Middle-Abundant mRNAs ADELHEID VIEBROCK, from Neurospora crassa ANGELA PERZ, AND WALTER SEBALD 254 25. Biogenesis of Cytochrome c in Neurospora crassa BERND HENNIG AND WALTER NEUPERT 261 26. Biosynthesis and Assembly of Nuclear-Coded RICHARD ZIMMERMANN Mitochondrial Membrane Proteins in Neurospora AND WALTER NEUPERT 275 crassa TABLE OF CONTENTS VÜ 27. Isolation and Properties of the Porin of the Outer Mitochondrial Membrane from Neurospora crassa 28. Synthesis and Assembly of Subunit 6 of the Mitochondrial ATPase in Yeast 29. Preparation and Use of Antibodies against Insoluble Membrane Proteins 30. Processing of Mitochondrial Polypeptide Precursors in Yeast 31. Pulse Labeling of Yeast Cells and Spheroplasts 32. Import of Polypeptides into Isolated Yeast Mitochondria 33. A Yeast Mitochondrial Chelator-Sensitive Protease That Processes Cytoplasmically Synthesized Protein Precursors: Isolation from Yeast and Assay 34. Selection and Characterization of Nuclear Genes Coding Mitochondrial Proteins: Genetic Complementation of Yeast pet Mutants 35. Transformation of Nuclear Respiratory Deficient Mutants of Yeast 36. Analysis of Yeast Mitochondrial Genes 37. Genetics and Biogenesis of Cytochrome b 38. Synthesis and Intracellular Transport of Mitochondrial Matrix Proteins in Rat Liver: Studies in Vivo and in Vitro 39. Biosynthesis of Cytochrome c and Its Posttranslational Transfer into Mitochondria 40. Isolation of Mammalian Mitochondrial DNA and RNA and Cloning of the Mitochondrial Genome 41. Analysis of Human Mitochondrial RNA
Biochemical Journal, 1992
The 20.9 kDa subunit of NADH:ubiquinone oxidoreductase (complex I) from Neurospora crassa is a nuclear-coded component of the hydrophobic arm of the enzyme. We have determined the primary structure of this subunit by sequencing a full-length cDNA and a cleavage product of the isolated polypeptide. The deduced protein sequence is 189 amino acid residues long and contains a putative membrane-spanning domain. Striking similarity over a 60 amino-acid-residue domain with the M (matrix) protein of para-influenza virus was found. No other relationship with already known sequences could be detected, leaving the function of this subunit in complex I still undefined. The biogenetic pathway of this polypeptide was studied using a mitochondrial import system in vitro. The 20.9 kDa subunit synthesized in vitro is efficiently imported into isolated mitochondria, where it obtains distinct features of the endogenous subunit. Our results suggest that the 20.9 kDa polypeptide is made on cytosolic rib...
Different Transport Pathways of Individual Precursor Proteins in Mitochondria
European Journal of Biochemistry, 1981
Transport of mitochondrial precursor proteins into mitochondria of Neurospora crassa was studied in a cellfree reconstituted system. Precursors were synthesized in a reticulocyte lysate programmed with Neurospora mRNA and transported into isolated mitochondria in the absence of protein synthesis. Uptake of the following precursors was investigated: apocytochrome c, ADP/ATP carrier and subunit 9 of the oligomycin‐sensitive ATPase.Addition of high concentrations of unlabelled chemically prepared apocytochrome c (1–10 μM) inhibited the appearance in the mitochondrial of labelled cytochrome c synthesized in vitro because the unlabelled protein dilutes the labelled one and because the translocation system has a limited capacity [apparent V is 1–3 pmol × min−1× (mg mitochondrial protein)−1]. Concentrations of added apocytochrome c exceeding the concentrations of precursor proteins synthesized in vitro by a factor of about 104 did not inhibit the transfer of ADP/ATP carrier or ATPase subun...
The TOM Core Complex: The General Protein Import Pore of the Outer Membrane of Mitochondria
The Journal of Cell Biology, 1999
Translocation of nuclear-encoded preproteins across the outer membrane of mitochondria is mediated by the multicomponent transmembrane TOM complex. We have isolated the TOM core complex of Neurospora crassa by removing the receptors Tom70 and Tom20 from the isolated TOM holo complex by treatment with the detergent dodecyl maltoside. It consists of Tom40, Tom22, and the small Tom components, Tom6 and Tom7. This core complex was also purified directly from mitochondria after solubilization with dodecyl maltoside. The TOM core complex has the characteristics of the general insertion pore; it contains high-conductance channels and binds preprotein in a targeting sequence-dependent manner. It forms a double ring structure that, in contrast to the holo complex, lacks the third density seen in the latter particles. Three-dimensional reconstruction by electron tomography exhibits two open pores traversing the complex with a diameter of ∼2.1 nm and a height of ∼7 nm. Tom40 is the key structu...
The protein import receptor of mitochondria
Trends in biochemical sciences, 1995
Protein import into the mitochondria of Saccharomyces cerevisiae depends on two receptor subcomplexes composed of integral outer-membrane proteins. One subcomplex is the MAS37-MAS70 heterodimer, which preferentially recognizes the mature regions of precursor proteins associated with ATP-dependent cytosolic chaperones. The other subcomplex contains the acidic proteins MAS20 and MAS22, which recognize the positively charged targeting sequences of a wide variety of mitochondrial precursors. We propose that the two subcomplexes can act together as a single, multifunctional receptor that binds simultaneously to different regions of a precursor molecule.
Mitochondrial protein import machinery and targeting information
Plant Science, 2002
During evolution, eukaryotic cells have acquired subcellular compartments, such as nuclei, peroxisomes, mitochondria, and, in the case of plant cells, chloroplasts, this compartmentalization allowing the cell to function more efficiently. Although, mitochondria and chloroplasts possess their own genomes, these have a low coding content and nuclear-encoded proteins have to be imported. Since the organization, content and functioning of organelles are strictly defined, an efficient and rigorous system for importing proteins synthesized in the cytosol is required. Most mitochondrial precursors synthesized in the cytosol are recognized and/or maintained in an unfolded conformation by cytosolic chaperone proteins and are then recognized by translocases of the mitochondrial outer and inner membranes (TOM and TIM, respectively), which transport them across the two membranes. The mechanism of mitochondrial protein import is thought to be well conserved across species. However, while many studies have investigated mitochondrial import in fungi, few have been carried out in plants, although it is clear that differences exist between fungi, mammals, and plants as regards the mitochondrial import system. In plants, for instance, the presence of both chloroplasts and mitochondria, with similar import mechanisms, might have rendered the import system more stringent. We will review the literature concerning the mitochondrial import machinery and the structure of mitochondrial presequences, paying particular attention to those features specific to plants.