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.