title: Proteins at the polypeptide tunnel exit of the yeast mitochondrial ribosome.
abstract: Oxidative phosphorylation in mitochondria requires the synthesis of proteins encoded in the mitochondrial DNA. The mitochondrial translation machinery differs significantly from that of the bacterial ancestor of the organelle. This is especially evident from many mitochondria-specific ribosomal proteins. An important site of the ribosome is the polypeptide tunnel exit. Here, nascent chains are exposed to an aqueous environment for the first time. Many biogenesis factors interact with the tunnel exit of pro- and eukaryotic ribosomes to help the newly synthesized proteins to mature. To date, nothing is known about the organization of the tunnel exit of mitochondrial ribosomes. We therefore undertook a comprehensive approach to determine the composition of the yeast mitochondrial ribosomal tunnel exit. Mitochondria contain homologues of the ribosomal proteins located at this site in bacterial ribosomes. Here, we identified proteins located in their proximity by chemical cross-linking and mass spectrometry. Our analysis revealed a complex network of interacting proteins including proteins and protein domains specific to mitochondrial ribosomes. This network includes Mba1, the membrane-bound ribosome receptor of the inner membrane, as well as Mrpl3, Mrpl13, and Mrpl27, which constitute ribosomal proteins exclusively found in mitochondria. This unique architecture of the tunnel exit is presumably an adaptation of the translation system to the specific requirements of the organelle.
authors.affiliation: Abteilung Zellbiologie, Technische Universität Kaiserslautern, 67663 Kaiserslautern, Germany.
authors.forename: Steffi
authors.initials: S
authors.lastname: Gruschke
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gröne
authors.forename: Manfred
authors.initials: M
authors.lastname: Heublein
authors.forename: Stefanie
authors.initials: S
authors.lastname: Hölz
authors.forename: Lars
authors.initials: L
authors.lastname: Israel
authors.forename: Axel
authors.initials: A
authors.lastname: Imhof
authors.forename: Johannes M
authors.initials: JM
authors.lastname: Herrmann
authors.forename: Martin
authors.initials: M
authors.lastname: Ott
mesh_terms: D002462:Cell Membrane / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D020285:Cryoelectron Microscopy / Q000379:methods; D004272:DNA, Mitochondrial / Q000378:metabolism; D013058:Mass Spectrometry / Q000379:methods; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000737:chemistry* / Q000378:metabolism*; D018384:Oxidative Stress; D010455:Peptides / Q000737:chemistry*; D010766:Phosphorylation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D012269:Ribosomal Proteins / Q000737:chemistry*; D012270:Ribosomes / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D003432:Cross-Linking Reagents; D004272:DNA, Mitochondrial; C100490:MBA1 protein, S cerevisiae; C489211:MRPL13 protein, S cerevisiae; C550930:MRPL3 protein, S cerevisiae; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010455:Peptides; D012269:Ribosomal Proteins; D029701:Saccharomyces cerevisiae Proteins; C072325:mitochondrial ribosomal protein YmL27
references.citation: EMBO J. 2006 Apr 19;25(8):1603-10
references.pmid: 16601683
references.citation: J Biol Chem. 2005 Apr 1;280(13):13004-11
references.pmid: 15654078
references.citation: J Biol Chem. 2001 Nov 23;276(47):43958-69
references.pmid: 11551941
references.citation: Mol Cell. 2009 May 15;34(3):344-53
references.pmid: 19450532
references.citation: Mol Biol Cell. 2009 May;20(10):2615-25
references.pmid: 19339279
references.citation: Cell. 1978 Nov;15(3):705-23
references.pmid: 153200
references.citation: Prog Nucleic Acid Res Mol Biol. 2004;77:211-61
references.pmid: 15196894
references.citation: EMBO J. 2003 Dec 15;22(24):6448-57
references.pmid: 14657018
references.citation: Eukaryot Cell. 2009 Nov;8(11):1792-802
references.pmid: 19783770
references.citation: Nucleic Acids Res. 2007;35(14):4686-703
references.pmid: 17604309
references.citation: Science. 2000 Aug 11;289(5481):905-20
references.pmid: 10937989
references.citation: Nucleic Acids Res. 1996 Sep 1;24(17):3469-71
references.pmid: 8811105
references.citation: J Cell Biol. 2005 Jul 4;170(1):27-35
references.pmid: 15983062
references.citation: J Biol Chem. 2001 Aug 31;276(35):33181-95
references.pmid: 11402041
references.citation: Eukaryot Cell. 2005 Feb;4(2):337-45
references.pmid: 15701796
references.citation: J Biol Chem. 1982 Nov 10;257(21):13028-33
references.pmid: 6290489
references.citation: Cell. 2003 Oct 3;115(1):97-108
references.pmid: 14532006
references.citation: EMBO J. 1985 Aug;4(8):2087-92
references.pmid: 3905388
references.citation: EMBO J. 2003 Dec 15;22(24):6438-47
references.pmid: 14657017
references.citation: J Cell Biol. 2001 May 28;153(5):1085-96
references.pmid: 11381092
references.citation: Nat Struct Mol Biol. 2009 Jun;16(6):589-97
references.pmid: 19491936
references.citation: Proc Natl Acad Sci U S A. 2009 Jun 16;106(24):9637-42
references.pmid: 19497863