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Published on: March 14, 2014
Localization of mRNAs encoding human mitochondrial oxidative phosphorylation proteins
Shinya Matsumoto1, Takeshi Uchiumi, Toshiro Saito
1Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan.
Mitochondrion
|March 13, 2012
Summary
Nuclear-encoded mitochondrial oxidative phosphorylation (OXPHOS) mRNAs encoding hydrophobic proteins localize near mitochondria. The Y-box binding protein-1 binds these OXPHOS mRNAs, impacting mitochondrial protein import.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Mitochondrial oxidative phosphorylation (OXPHOS) relies on proteins encoded by both nuclear and mitochondrial DNA.
- Nuclear-encoded OXPHOS mRNAs exhibit specific subcellular localizations, but their proximity to mitochondria is not well understood.
Purpose of the Study:
- To investigate the subcellular localization of nuclear-encoded OXPHOS mRNAs relative to mitochondria.
- To identify factors involved in the mitochondrial targeting of these mRNAs.
Main Methods:
- Comparison of mRNA populations in mitochondria-bound polysome fractions versus free cytosolic polysome fractions.
- Analysis of transmembrane domains in OXPHOS proteins.
- Investigation of the RNA-binding protein Y-box binding protein-1 (YBX1) localization and binding to OXPHOS mRNAs.
Main Results:
- mRNAs encoding hydrophobic OXPHOS proteins, destined for the inner mitochondrial membrane, were found localized near mitochondria.
- OXPHOS mRNAs with fewer than one transmembrane domain were predominantly localized in the cytosol.
- Y-box binding protein-1 was identified at the mitochondrial outer membrane, bound to OXPHOS mRNAs.
Conclusions:
- Specific OXPHOS mRNAs are targeted to mitochondrial vicinity for co-translational import.
- Hydrophobicity and transmembrane domain count correlate with mRNA localization.
- Y-box binding protein-1 plays a role in the mitochondrial association of OXPHOS mRNAs.
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