The transport machinery for the import of preproteins across the outer mitochondrial membrane

Michael T. Ryan, Richard Wagner, Nikolaus Pfanner

Research output: Contribution to journalArticleResearchpeer-review

32 Citations (Scopus)


In order for proteins to be imported into subcellular compartments, they must first traverse the organellar membranes. In mitochondria, hydrophilic protein channels in both the outer and inner membranes serve such a purpose. Recently, the channel protein of the outer mitochondrial membrane was identified to be Tom40. Tom40 is found in a high molecular weight complex termed the general import pore (GIP) complex where it is tightly associated with the receptor protein Tom22 along with Tom7, Tom6 and Tom5. Tom7 and Tom6 seem to modulate the dynamics of the GIP complex while Tom5 is involved in preprotein transfer from receptors to Tom40. The receptor proteins Tom70 and Tom20 associate with this complex in a weaker manner where they are involved in the initial recognition of preproteins. This review focuses on the identification and characterisation of the transport machinery of the outer mitochondrial membrane and how they are involved in the co-ordination and regulation of events required for the translocation of preproteins into mitochondria.

Original languageEnglish
Pages (from-to)13-21
Number of pages9
JournalInternational Journal of Biochemistry & Cell Biology
Issue number1
Publication statusPublished - 1 Jan 2000
Externally publishedYes


  • Biogenesis
  • Mitochondria
  • Protein import
  • TOM
  • Translocation

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