The carboxyl-terminal two-thirds of the ADP/ATP carrier polypeptide contains sufficient information to direct translocation into mitochondria.
The precursor of the mitochondrial inner membrane protein ADP/ATP carrier is cytoplasmically synthesized without an amino-terminal peptide extension. We constructed a truncated precursor lacking the 103 amino acids from the amino terminus (about a third of the protein). Import of the truncated precursor into mitochondria showed the import characteristics of the authentic precursor, including nucleoside triphosphate dependence, requirement for a protease-sensitive component on the mitochondrial surface, two-step specific binding to the outer membrane, and membrane potential-dependent translocation into the inner membrane. We conclude that, in contrast to all other mitochondrial precursor proteins studied so far, domains of the ADP/ATP carrier distant from the amino terminus can carry specific targeting information for transport into mitochondria.
Pfanner
N
N
Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.
Hoeben
P
P
Tropschug
M
M
Neupert
W
W
D000818:Animals; D003001:Cloning, Molecular; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology*; D000226:Mitochondrial ADP, ATP Translocases / Q000235:genetics* / Q000378:metabolism; D009491:Neurospora / Q000201:enzymology*; D009492:Neurospora crassa / Q000201:enzymology* / Q000235:genetics; D009713:Nucleotidyltransferases / Q000235:genetics*; D014176:Protein Biosynthesis; D011499:Protein Processing, Post-Translational; D012156:Reticulocytes / Q000378:metabolism
D000226:Mitochondrial ADP, ATP Translocases; D009713:Nucleotidyltransferases