Coenzyme Q biosynthetic proteins assemble in a substrate-dependent manner into domains at ER-mitochondria contacts

J Cell Biol. 2019 Apr 1;218(4):1353-1369. doi: 10.1083/jcb.201808044. Epub 2019 Jan 23.

Abstract

Coenzyme Q (CoQ) lipids are ancient electron carriers that, in eukaryotes, function in the mitochondrial respiratory chain. In mitochondria, CoQ lipids are built by an inner membrane-associated, multicomponent, biosynthetic pathway via successive steps of isoprenyl tail polymerization, 4-hydroxybenzoate head-to-tail attachment, and head modification, resulting in the production of CoQ. In yeast, we discovered that head-modifying CoQ pathway components selectively colocalize to multiple resolvable domains in vivo, representing supramolecular assemblies. In cells engineered with conditional ON or OFF CoQ pathways, domains were strictly correlated with CoQ production and substrate flux, respectively, indicating that CoQ lipid intermediates are required for domain formation. Mitochondrial CoQ domains were also observed in human cells, underscoring their conserved functional importance. CoQ domains within cells were highly enriched adjacent to ER-mitochondria contact sites. Together, our data suggest that CoQ domains function to facilitate substrate accessibility for processive and efficient CoQ production and distribution in cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line, Tumor
  • Endoplasmic Reticulum / enzymology*
  • Endoplasmic Reticulum / genetics
  • Enzymes / genetics
  • Enzymes / metabolism*
  • Humans
  • Mitochondria / enzymology*
  • Mitochondria / genetics
  • Mitochondrial Proteins / genetics
  • Mitochondrial Proteins / metabolism*
  • Multienzyme Complexes
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Substrate Specificity
  • Ubiquinone / biosynthesis*
  • Ubiquinone / genetics
  • Ubiquinone / metabolism

Substances

  • Enzymes
  • Mitochondrial Proteins
  • Multienzyme Complexes
  • Saccharomyces cerevisiae Proteins
  • Ubiquinone
  • ubiquinone 9