Mitochondrial Protein Interaction Mapping Identifies Regulators of Respiratory Chain Function

Mol Cell. 2016 Aug 18;63(4):621-632. doi: 10.1016/j.molcel.2016.06.033. Epub 2016 Aug 4.

Abstract

Mitochondria are essential for numerous cellular processes, yet hundreds of their proteins lack robust functional annotation. To reveal functions for these proteins (termed MXPs), we assessed condition-specific protein-protein interactions for 50 select MXPs using affinity enrichment mass spectrometry. Our data connect MXPs to diverse mitochondrial processes, including multiple aspects of respiratory chain function. Building upon these observations, we validated C17orf89 as a complex I (CI) assembly factor. Disruption of C17orf89 markedly reduced CI activity, and its depletion is found in an unresolved case of CI deficiency. We likewise discovered that LYRM5 interacts with and deflavinates the electron-transferring flavoprotein that shuttles electrons to coenzyme Q (CoQ). Finally, we identified a dynamic human CoQ biosynthetic complex involving multiple MXPs whose topology we map using purified components. Collectively, our data lend mechanistic insight into respiratory chain-related activities and prioritize hundreds of additional interactions for further exploration of mitochondrial protein function.

Keywords: C15orf48; C2orf47; DHRS4.

MeSH terms

  • Databases, Protein
  • Electron Transport Chain Complex Proteins / genetics
  • Electron Transport Chain Complex Proteins / metabolism*
  • Electron Transport Complex I / metabolism
  • HEK293 Cells
  • Hep G2 Cells
  • Humans
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Protein Interaction Mapping / methods*
  • Protein Interaction Maps*
  • Proteomics / methods*
  • RNA Interference
  • Signal Transduction
  • Transfection
  • Ubiquinone / metabolism

Substances

  • Electron Transport Chain Complex Proteins
  • Mitochondrial Proteins
  • Ubiquinone
  • Electron Transport Complex I