title: Assembly factors for the membrane arm of human complex I.
abstract: Mitochondrial respiratory complex I is a product of both the nuclear and mitochondrial genomes. The integration of seven subunits encoded in mitochondrial DNA into the inner membrane, their association with 14 nuclear-encoded membrane subunits, the construction of the extrinsic arm from 23 additional nuclear-encoded proteins, iron-sulfur clusters, and flavin mononucleotide cofactor require the participation of assembly factors. Some are intrinsic to the complex, whereas others participate transiently. The suppression of the expression of the NDUFA11 subunit of complex I disrupted the assembly of the complex, and subcomplexes with masses of 550 and 815 kDa accumulated. Eight of the known extrinsic assembly factors plus a hydrophobic protein, C3orf1, were associated with the subcomplexes. The characteristics of C3orf1, of another assembly factor, TMEM126B, and of NDUFA11 suggest that they all participate in constructing the membrane arm of complex I.
authors.affiliation: Medical Research Council Mitochondrial Biology Unit, Cambridge CB2 0XY, United Kingdom.
authors.forename: Byron
authors.initials: B
authors.lastname: Andrews
authors.forename: Joe
authors.initials: J
authors.lastname: Carroll
authors.forename: Shujing
authors.initials: S
authors.lastname: Ding
authors.forename: Ian M
authors.initials: IM
authors.lastname: Fearnley
authors.forename: John E
authors.initials: JE
authors.lastname: Walker
mesh_terms: D015153:Blotting, Western; D045744:Cell Line, Tumor; D042967:Electron Transport Complex I / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D013058:Mass Spectrometry; D008565:Membrane Proteins / Q000378:metabolism*; D018613:Microscopy, Confocal; D033681:Mitochondrial Membrane Transport Proteins; D051336:Mitochondrial Membranes / Q000378:metabolism*; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D010101:Oxygen Consumption / Q000502:physiology; D055503:Protein Multimerization / Q000502:physiology*
chemical_list: D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; C528082:NDUFA11 protein, human; C421265:TIMMDC1 protein, human; C585774:TMEM126B protein, human; D042967:Electron Transport Complex I
keywords: NADH:ubiquinone oxidoreductase; mitochondria; respiratory chain