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OM14 is a mitochondrial receptor for cytosolic ribosomes that supports co-translational import into mitochondria

Chen Lesnik1, Yifat Cohen2, Avigail Atir-Lande1

  • 1Department of Biology, Technion-Israel Institute of Technology, Haifa 3200003, Israel.

Nature Communications
|December 10, 2014
PubMed

Insights

Researchers identified OM14 as the mitochondrial receptor for the nascent chain-associated complex (NAC), supporting co-translational protein import into mitochondria. This discovery highlights OM14's crucial role in mitochondrial protein targeting.

Area of Science:

  • Mitochondrial biology
  • Molecular cell biology
  • Protein import mechanisms

Background:

  • Mitochondrial protein import is essential for cellular function.
  • Traditionally, proteins are imported post-translationally after cytosolic synthesis.
  • A co-translational import model, involving ribosome association with mitochondria, has been proposed but lacked key receptor identification.

Purpose of the Study:

  • To identify the mitochondrial receptor for the ribosome-associated chaperone, nascent chain-associated complex (NAC).
  • To investigate the role of this receptor in co-translational mitochondrial protein import.

Main Methods:

  • Genetic deletion analysis of the Saccharomyces cerevisiae outer membrane protein OM14.
  • Biochemical assays to quantify NAC and ribosome association with mitochondria.
  • Mitochondrial import assays to measure protein import efficiency.

Main Results:

  • Mitochondria lacking OM14 (OM14Δ) showed reduced association of NAC and ribosomes.
  • Ribosomes from NAC-deficient cells exhibited decreased OM14 association.
  • Import assays demonstrated significantly reduced protein import into OM14Δ mitochondria.
  • OM14-dependent import was shown to require NAC.

Conclusions:

  • OM14 is identified as the first mitochondrial outer membrane receptor for ribosome-associated NAC.
  • OM14 plays a critical role in facilitating co-translational protein import into mitochondria.
  • These findings provide strong support for the co-translational import model into mitochondria.

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