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OM14 is a mitochondrial receptor for cytosolic ribosomes that supports co-translational import into mitochondria.
Nat Commun. 2014 Dec 9;5:5711. doi: 10.1038/ncomms6711
Lesnik C(), Cohen Y(), Atir-Lande A(), Schuldiner M(), Arava Y()
Abstract:
It is well established that import of proteins into mitochondria can occur after their complete synthesis by cytosolic ribosomes. Recently, an additional model was revived, proposing that some proteins are imported co-translationally. This model entails association of ribosomes with the mitochondrial outer membrane, shown to be mediated through the ribosome-associated chaperone nascent chain-associated complex (NAC). However, the mitochondrial receptor of this complex is unknown. Here, we identify the Saccharomyces cerevisiae outer membrane protein OM14 as a receptor for NAC. OM14Δ mitochondria have significantly lower amounts of associated NAC and ribosomes, and ribosomes from NAC[Δ] cells have reduced levels of associated OM14. Importantly, mitochondrial import assays reveal a significant decrease in import efficiency into OM14Δ mitochondria, and OM14-dependent import necessitates NAC. Our results identify OM14 as the first mitochondrial receptor for ribosome-associated NAC and reveal its importance for import. These results provide a strong support for an additional, co-translational mode of import into mitochondria.
PMID: 25487825
Free Full-Text: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4268710/