Recent surprises in protein targeting to mitochondria and plastids

Curr Opin Plant Biol. 2006 Dec;9(6):610-5. doi: 10.1016/j.pbi.2006.09.002. Epub 2006 Sep 27.


The functions of mitochondria and chloroplasts rely on thousands of proteins, mostly imported from the cytosol through specialized import channels. Neither the detailed import mechanisms nor the identities of all targeted proteins are known. Recent surprises include unexpected results concerning import receptors, unexpectedly frequent dual-targeting of proteins, and the discovery of novel routes of protein trafficking. Such findings make it more difficult to predict which proteins really are targeted to organelles. By combining experimental and bioinformatics data, we estimate the size of the mitochondrial and plastid proteomes to be approximately 2000 and 2700 proteins, respectively. Advances in cell and organelle fractionation coupled with modern proteomics techniques are probably the best route to understanding organellar protein composition.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Mitochondria / metabolism*
  • Plant Proteins / metabolism*
  • Plastids / metabolism*
  • Protein Transport


  • Plant Proteins