MidA is a putative methyltransferase that is required for mitochondrial complex I function.
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Carilla-Latorre S, Gallardo ME, Annesley SJ, Calvo-Garrido J, Grana O, Accari SL, Smith PK, Valencia A, Garesse R, Fisher PR, Escalante R
MidA is a putative methyltransferase that is required for mitochondrial complex I function.
J Cell Sci. 2010 May 15;123(Pt 10):1674-83. doi: 10.1242/jcs.066076. Epub 2010 Apr 20.
- PubMed ID
- 20406883 [ View in PubMed]
- Abstract
Dictyostelium and human MidA are homologous proteins that belong to a family of proteins of unknown function called DUF185. Using yeast two-hybrid screening and pull-down experiments, we showed that both proteins interact with the mitochondrial complex I subunit NDUFS2. Consistent with this, Dictyostelium cells lacking MidA showed a specific defect in complex I activity, and knockdown of human MidA in HEK293T cells resulted in reduced levels of assembled complex I. These results indicate a role for MidA in complex I assembly or stability. A structural bioinformatics analysis suggested the presence of a methyltransferase domain; this was further supported by site-directed mutagenesis of specific residues from the putative catalytic site. Interestingly, this complex I deficiency in a Dictyostelium midA(-) mutant causes a complex phenotypic outcome, which includes phototaxis and thermotaxis defects. We found that these aspects of the phenotype are mediated by a chronic activation of AMPK, revealing a possible role of AMPK signaling in complex I cytopathology.