| First Author | Zurita Rendón O | Year | 2014 |
| Journal | Hum Mol Genet | Volume | 23 |
| Issue | 19 | Pages | 5159-70 |
| PubMed ID | 24838397 | Mgi Jnum | J:214316 |
| Mgi Id | MGI:5588758 | Doi | 10.1093/hmg/ddu239 |
| Citation | Zurita Rendon O, et al. (2014) The arginine methyltransferase NDUFAF7 is essential for complex I assembly and early vertebrate embryogenesis. Hum Mol Genet 23(19):5159-70 |
| abstractText | Complex I of the mitochondrial respiratory chain is a large multisubunit enzyme that assembles from nuclear and mtDNA-encoded components. Several complex I assembly factors have been identified, but their precise functions are not well understood. Here, we have investigated the function of one of these, NDUFAF7, a soluble matrix protein comprised of a DUF185 domain that harbors a methyltransferase motif. Knockdown of NDUFAF7 by siRNA in human fibroblasts produced a specific complex I assembly defect, as did morpholino-mediated knockdown of the zebrafish ortholog. Germline disruption of the murine ortholog was an early embryonic lethal. The complex I assembly defect was characterized by rapid, AFG3L2-dependent, turnover of newly synthesized ND1, the subunit that seeds the assembly pathway, and by decreased steady-state levels of several other structural subunits including NDUFS2, NDUFS1 and NDUFA9. Expression of an NDUFAF7 mutant (G124V), predicted to disrupt methyltransferase activity, impaired complex I assembly, suggesting an assembly factor or structural subunit as a substrate for methylation. To identify the NDUFAF7 substrate, we used an anti-ND1 antibody to immunoprecipitate complex I and its associated assembly factors, followed by mass spectrometry to detect posttranslational protein modifications. Analysis of an NDUFAF7 methyltransferase mutant showed a 10-fold reduction in an NDUFS2 peptide containing dimethylated Arg85, but a 5-fold reduction in three other NDUFS2 peptides. These results show that NDUFAF7 functions to methylate NDUFS2 after it assembles into a complex I, stabilizing an early intermediate in the assembly pathway, and that this function is essential for normal vertebrate development. |
