Complexome Profiling Reveals Association of PPR Proteins with Ribosomes in the Mitochondria of Plants

Mol Cell Proteomics. 2019 Jul;18(7):1345-1362. doi: 10.1074/mcp.RA119.001396. Epub 2019 Apr 25.


Mitochondrial transcripts are subject to a wealth of processing mechanisms including cis- and trans-splicing events, as well as base modifications (RNA editing). Hundreds of proteins are required for these processes in plant mitochondria, many of which belong to the pentatricopeptide repeat (PPR) protein superfamily. The structure, localization, and function of these proteins is only poorly understood. Here we present evidence that several PPR proteins are bound to mitoribosomes in plants. A novel complexome profiling strategy in combination with chemical crosslinking has been employed to systematically define the protein constituents of the large and the small ribosomal subunits in the mitochondria of plants. We identified more than 80 ribosomal proteins, which include several PPR proteins and other non-conventional ribosomal proteins. These findings reveal a potential coupling of transcriptional and translational events in the mitochondria of plants. Furthermore, the data indicate an extremely high molecular mass of the "small" subunit, even exceeding that of the "large" subunit.

Keywords: Crosslinking; Mitochondria function or biology; PPR; Plant Biology*; Ribosomes*; Translation*; complexome; mitochondria; plant; ribosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / metabolism*
  • Bacteria / metabolism
  • Mitochondria / metabolism*
  • Mitochondrial Proteins / metabolism
  • Molecular Weight
  • Multiprotein Complexes / metabolism*
  • Plant Leaves / metabolism
  • Protein Subunits / metabolism
  • Proteomics*
  • Ribosomal Proteins / metabolism
  • Ribosome Subunits, Large / metabolism
  • Ribosome Subunits, Small / metabolism
  • Ribosomes / metabolism*


  • Arabidopsis Proteins
  • Mitochondrial Proteins
  • Multiprotein Complexes
  • Protein Subunits
  • Ribosomal Proteins