The preprotein translocase of the inner mitochondrial membrane: evolutionary conservation of targeting and assembly of Tim17

J Mol Biol. 1996 Oct 4;262(4):389-95. doi: 10.1006/jmbi.1996.0522.


The preprotein translocase of the inner mitochondrial membrane has only been described in Saccharomyces cerevisiae to date. We report that the essential subunit Tim17 is highly conserved in evolution. The targeting and assembly of yeast Tim17 as well as that of human and Drosophila melanogaster Tim17 were characterized with isolated yeast mitochondria. Targeting signals in the mature protein direct the Tim17 precursors to the receptor Tom70 on the mitochondrial surface. In a membrane potential-dependent step the precursors insert into the inner membrane, adopt a characteristic topology and assemble with Tim23. The mechanisms of targeting and assembly were indistinguishable between the Tim17s from distinct organisms, indicating a high evolutionary conservation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry
  • Adenosine Triphosphatases / genetics*
  • Amino Acid Sequence
  • Animals
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics*
  • Base Sequence
  • Biological Transport
  • Carrier Proteins / biosynthesis
  • Carrier Proteins / genetics*
  • Conserved Sequence*
  • Drosophila melanogaster
  • Escherichia coli Proteins*
  • Humans
  • Intracellular Membranes / enzymology
  • Membrane Proteins / biosynthesis
  • Membrane Proteins / genetics*
  • Membrane Transport Proteins*
  • Mitochondria / enzymology*
  • Mitochondrial Membrane Transport Proteins
  • Molecular Sequence Data
  • Protein Conformation
  • Rats
  • Repressor Proteins*
  • SEC Translocation Channels
  • Saccharomyces cerevisiae
  • Saccharomyces cerevisiae Proteins*
  • SecA Proteins


  • Bacterial Proteins
  • Carrier Proteins
  • Escherichia coli Proteins
  • Membrane Proteins
  • Membrane Transport Proteins
  • Mitochondrial Membrane Transport Proteins
  • Repressor Proteins
  • SEC Translocation Channels
  • Saccharomyces cerevisiae Proteins
  • TIM17 protein, S cerevisiae
  • TIM23 protein, S cerevisiae
  • Adenosine Triphosphatases
  • SecA Proteins

Associated data

  • GENBANK/D74501
  • GENBANK/D74639
  • GENBANK/D75891
  • GENBANK/X74161
  • GENBANK/X77796
  • GENBANK/X97544
  • GENBANK/Z46191