Article
Solution structure and siRNA-mediated knockdown analysis of the mitochondrial disease-related protein C12orf65
Article first published online: 10 AUG 2012
DOI: 10.1002/prot.24152
Copyright © 2012 Wiley Periodicals, Inc.
Issue

Proteins: Structure, Function, and Bioinformatics
Volume 80, Issue 11, pages 2629–2642, November 2012
Additional Information
How to Cite
Kogure, H., Hikawa, Y., Hagihara, M., Tochio, N., Koshiba, S., Inoue, Y., Güntert, P., Kigawa, T., Yokoyama, S. and Nameki, N. (2012), Solution structure and siRNA-mediated knockdown analysis of the mitochondrial disease-related protein C12orf65. Proteins, 80: 2629–2642. doi: 10.1002/prot.24152
Publication History
- Issue published online: 4 OCT 2012
- Article first published online: 10 AUG 2012
- Accepted manuscript online: 21 JUL 2012 05:56AM EST
- Manuscript Accepted: 5 JUL 2012
- Manuscript Revised: 27 JUN 2012
- Manuscript Received: 17 APR 2012
Funded by
- Grant-in-Aid for Scientific Research (C) from the Ministry of Education, Culture, Sports, Science and Technology (MEXT) of Japan. Grant Number: 23570205
- Lichtenberg program of the Volkswagen Foundation
Keywords:
- flow cytometry;
- GGQ domain;
- ICT1;
- mitochondria;
- NMR;
- release factor;
- ribosome rescue;
- YaeJ
Abstract
Loss of function of the c12orf65 gene causes a mitochondrial translation defect, leading to encephalomyopathy. The C12orf65 protein is thought to play a role similar to that of ICT1 in rescuing stalled mitoribosomes during translation. Both proteins belong to a family of Class I peptide release factors (RFs), all characterized by the presence of a GGQ motif. Here, we determined the solution structure of the GGQ-containing domain (GGQ domain) of C12orf65 from mouse by NMR spectroscopy, and examined the effect of siRNA-mediated knockdown of C12orf65 on mitochondria in HeLa cells using flow cytometry. The GGQ domain, comprising residues 60–124 of the 184-residue full-length protein, forms a structure with a 310-β1-β2-β3-α1 topology that resembles the GGQ domain structure of RF more closely than that of ICT1. Thus, the GGQ domain structures of this protein family can be divided into two types, depending on the region linking β2 and β3; the C12orf65/RF type having a 6-residue π-HB turn and the ICT1 type having an α-helix. Knockdown of C12orf65 resulted in increased ROS production and apoptosis, leading to inhibition of cell proliferation. Substantial changes in mitochondrial membrane potential and mass in the C12orf65-knockdown cells were observed compared with the control cells. These results indicate that the function of C12orf65 is essential for cell vitality and mitochondrial function. Although similar effects were observed in ICT1-downregulated cells, there were significant differences in the range and pattern of the effects between C12orf65- and ICT1-knockdown cells, suggesting different roles of C12orf65 and ICT1 in rescuing stalled mitoribosomes. Proteins 2012. © 2012 Wiley Periodicals, Inc.

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