Yamano K, et al. (2005) The phosphate carrier has an ability to be sorted to either the TIM22 pathway or the TIM23 pathway for its import into yeast mitochondria. J Biol Chem 280(11):10011-7
Abstract: Most mitochondrial proteins are synthesized in the cytosol, imported into mitochondria via the TOM40 complex, and follow several distinct sorting pathways to reach their destination submitochondrial compartments. Phosphate carrier (PiC) is an inner membrane protein with 6 transmembrane segments (TM1-TM6) and requires, after translocation across the outer membrane, the Tim9-Tim10 complex and the TIM22 complex to be inserted into the inner membrane. Here we analyzed in vitro import of fusion proteins between various PiC segments and mouse dihydrofolate reductase. The fusion protein without TM1-TM2 was translocated across the outer membrane, but was not inserted into the inner membrane. The fusion proteins without TM1-TM4 were not inserted into the inner membrane, but instead translocated across the inner membrane. Functional defects of Tim50 of the TIM23 complex either by depletion of the protein or addition of anti-Tim50 antibodies blocked translocation of the fusion proteins without TM1-TM4 across the inner membrane, suggesting that lack of TM1-TM4 led to switch of its sorting pathway from the TIM22 pathway to the TIM23 pathway. PiC thus appears to have a latent signal for sorting to the TIM23 pathway, which is exposed by reduced interactions with the Tim9-Tim10 complex and maintenance of the import competence.
|Status: Published||Type: Journal Article||PubMed ID: 15644337|
Topics addressed in this paper
Number of different genes curated to this paper: 8
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