Import of proteins into mitochondria: a 70 kilodalton outer membrane protein with a large carboxy-terminal deletion is still transported to the outer membrane

EMBO J. 1983;2(12):2161-8.


The yeast mitochondrial outer membrane contains a major 70-kd protein which is coded by a nuclear gene. Two forms of this gene were isolated from a yeast genomic clone bank: the intact gene, and a truncated gene which had lost a large part of its 3' end during the cloning procedure. Upon transformation into yeast, both the intact and the truncated gene are expressed; the truncated gene generates a shortened protein missing 203 amino acids from the carboxy-terminus. This truncated polypeptide reacts with a monoclonal antibody against the authentic 70-kd protein and is transported to the mitochondrial outer membrane. By integrative transformation, we have constructed a yeast mutant which lacks the 70-kd protein and is unable to adapt to growth on a nonfermentable carbon source at 37 degrees C. This phenotypic lesion can be corrected by transforming the mutant with the intact, but not the truncated gene. The carboxy-terminal sequence of 203 amino acids is thus necessary for the function of the protein, but not for its targeting to the mitochondrion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cloning, Molecular*
  • DNA Restriction Enzymes
  • Escherichia coli / genetics
  • Fungal Proteins / genetics*
  • Membrane Proteins / genetics*
  • Mitochondria / metabolism*
  • Molecular Weight
  • Mutation
  • Nucleic Acid Hybridization
  • Protein Processing, Post-Translational*
  • RNA, Messenger / genetics
  • Saccharomyces cerevisiae / genetics*


  • Fungal Proteins
  • Membrane Proteins
  • RNA, Messenger
  • DNA Restriction Enzymes