Signal recognition initiates reorganization of the presequence translocase during protein import

EMBO J. 2013 Mar 20;32(6):886-98. doi: 10.1038/emboj.2013.23. Epub 2013 Feb 12.


The mitochondrial presequence translocase interacts with presequence-containing precursors at the intermembrane space (IMS) side of the inner membrane to mediate their translocation into the matrix. Little is known as too how these matrix-targeting signals activate the translocase in order to initiate precursor transport. Therefore, we analysed how signal recognition by the presequence translocase initiates reorganization among Tim-proteins during import. Our analyses revealed that the presequence receptor Tim50 interacts with Tim21 in a signal-sensitive manner in a process that involves the IMS-domain of the Tim23 channel. The signal-driven release of Tim21 from Tim50 promotes recruitment of Pam17 and thus triggers formation of the motor-associated form of the TIM23 complex required for matrix transport.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Membrane Proteins / chemistry
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Membrane Transport Proteins / chemistry
  • Membrane Transport Proteins / genetics
  • Membrane Transport Proteins / metabolism
  • Membrane Transport Proteins / physiology*
  • Mitochondrial Membrane Transport Proteins / chemistry
  • Mitochondrial Membrane Transport Proteins / genetics
  • Mitochondrial Membrane Transport Proteins / metabolism
  • Mitochondrial Membrane Transport Proteins / physiology
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Models, Molecular
  • Protein Binding
  • Protein Interaction Domains and Motifs / genetics
  • Protein Interaction Domains and Motifs / physiology
  • Protein Sorting Signals / genetics
  • Protein Sorting Signals / physiology*
  • Protein Structure, Secondary
  • Protein Transport* / genetics
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology
  • Substrate Specificity


  • Carrier Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Mitochondrial Membrane Transport Proteins
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Pam17 protein, S cerevisiae
  • Protein Sorting Signals
  • Saccharomyces cerevisiae Proteins
  • TIM23 protein, S cerevisiae
  • TIM50 protein, S cerevisiae
  • Tim21 protein, S cerevisiae