Pentatricopeptide repeat domain protein 3 associates with the mitochondrial small ribosomal subunit and regulates translation

Davies, Stefan M.K.; Rackham, Oliver; Shearwood, Anne-Marie J.; Hamilton, Kristina L.; Narsai, Reena; Whelan, James; Filipovska, Aleksandra

doi:10.1016/j.febslet.2009.04.048

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Volume 583, Issue 12 , Pages 1853-1858, 18 June 2009

Pentatricopeptide repeat domain protein 3 associates with the mitochondrial small ribosomal subunit and regulates translation

Edited by Michael Ibba

Stefan M.K. Davies
- Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Level 6, Medical Research Foundation Building, Rear 50 Murray Street, Perth, Western Australia 6000, Australia
- These authors contributed equally.
Oliver Rackham
- Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Level 6, Medical Research Foundation Building, Rear 50 Murray Street, Perth, Western Australia 6000, Australia
- These authors contributed equally.
Anne-Marie J. Shearwood
- Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Level 6, Medical Research Foundation Building, Rear 50 Murray Street, Perth, Western Australia 6000, Australia
Kristina L. Hamilton
- Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Level 6, Medical Research Foundation Building, Rear 50 Murray Street, Perth, Western Australia 6000, Australia
Reena Narsai
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Western Australia 6009, Australia
James Whelan
- Australian Research Council Centre of Excellence in Plant Energy Biology, University of Western Australia, Western Australia 6009, Australia
Aleksandra Filipovska
- Western Australian Institute for Medical Research, Centre for Medical Research, The University of Western Australia, Level 6, Medical Research Foundation Building, Rear 50 Murray Street, Perth, Western Australia 6000, Australia
- Corresponding author. Fax: +61 8 9224 0322.

Received 26 March 2009; received in revised form 21 April 2009; accepted 23 April 2009. published online 08 May 2009.

Abstract

The basic components and mechanisms of mitochondrial transcription in mammals have been described, however, the components involved in mRNA processing, translation and stability remain largely unknown. In plants, pentatricopeptide domain RNA-binding proteins regulate the stability, expression and translation of mitochondrial transcripts. Here, we investigated the role of an uncharacterized mammalian pentatricopeptide domain protein, pentatricopeptide repeat domain protein 3 (PTCD3), and showed that it is a mitochondrial protein that associates with the small subunit of mitochondrial ribosomes. PTCD3 knockdown and over expression did not affect mitochondrial mRNA levels, suggesting that PTCD3 is not involved in RNA processing and stability. However, lowering PTCD3 in 143B osteosarcoma cells decreased mitochondrial protein synthesis, mitochondrial respiration and the activity of Complexes III and IV, suggesting that PTCD3 has a role in mitochondrial translation.