Import of ADP/ATP carrier into mitochondria: two receptors act in parallel.
We have identified the yeast homologue of Neurospora crassa MOM72, the mitochondrial import receptor for the ADP/ATP carrier (AAC), by functional studies and by cDNA sequencing. Mitochondria of a yeast mutant in which the gene for MOM72 was disrupted were impaired in specific binding and import of AAC. Unexpectedly, we found a residual, yet significant import of AAC into mitochondria lacking MOM72 that occurred via the receptor MOM19. We conclude that both MOM72 and MOM19 can direct AAC into mitochondria, albeit with different efficiency. Moreover, the precursor of MOM72 apparently does not require a positively charged sequence at the extreme amino terminus for targeting to mitochondria.
Steger
H F
HF
Institut für Physiologische Chemie, Universität München, Federal Republic of Germany.
Söllner
T
T
Kiebler
M
M
Dietmeier
K A
KA
Pfaller
R
R
Trülzsch
K S
KS
Tropschug
M
M
Neupert
W
W
Pfanner
N
N
D000595:Amino Acid Sequence; D001483:Base Sequence; D004271:DNA, Fungal / Q000235:genetics; D005656:Fungal Proteins; D005800:Genes, Fungal; D007700:Kinetics; D008565:Membrane Proteins; D008928:Mitochondria / Q000201:enzymology*; D000226:Mitochondrial ADP, ATP Translocases / Q000235:genetics* / Q000378:metabolism; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009492:Neurospora crassa / Q000201:enzymology / Q000235:genetics*; D011499:Protein Processing, Post-Translational; D011956:Receptors, Cell Surface / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D012689:Sequence Homology, Nucleic Acid
D004271:DNA, Fungal; D005656:Fungal Proteins; D008565:Membrane Proteins; D033681:Mitochondrial Membrane Transport Proteins; D000090622:Mitochondrial Precursor Protein Import Complex Proteins; D011956:Receptors, Cell Surface; D018160:Receptors, Cytoplasmic and Nuclear; D029701:Saccharomyces cerevisiae Proteins; C489039:TOM70 protein, S cerevisiae; D000226:Mitochondrial ADP, ATP Translocases