Isolation of a cDNA clone specifying rat chaperonin 10, a stress-inducible mitochondrial matrix protein synthesised without a cleavable presequence

Michael T. Ryan, Nicholas J. Hoogenraad, Peter B. Høj

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We have isolated a cDNA clone encoding chaperonin 10 from rat liver. The cDNA specifies a protein of 102 amino acids which, when transcribed and translated in vitro, yields a single basic product (pI > 9) that co-migrates exactly with the heat shock inducible cpn10 of rat hepatoma cells during 2D gel-electrophoresis. It is concluded that cpn10, unlike the majority of nuclear-encoded proteins of the mitochondrial matrix, is synthesised without a cleavable targeting signal and that, following removal of the initiating methionine, it becomes acetylated prior to mitochondrial import. Incubation of 3H- or 35S-labelled cpn10 with mitochondria confirms these conclusions and shows that cpn10 is imported into mitochondria in an energy-dependent process which is inhibited by the presence of 2,4-dinitrophenol.

Original languageEnglish
Pages (from-to)152-156
Number of pages5
JournalFEBS Letters
Issue number2
Publication statusPublished - 10 Jan 1994
Externally publishedYes


  • Acetylation
  • Amphiphilic helix
  • Heat-shock protein
  • Protein import

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