Characterization of a Saccharomyces cerevisiae Gene That Encodes a Mitochondrial Phosphate Transporter--Like Protein

Abstract

The mitochondrial phosphate transporter of Saccharomyces cerevisiae, encoded by MIR1 (YJR077C) gene, shows divergence among the transporters in various eukaryotes. We have characterized another gene, YER053C, that appeared to encode an orthologous mitochondrial phosphate transporter of yeast. The predicted amino acid sequence of the YER053C protein is much more similar to that of mitochondrial phosphate transporters of other species than that of MIR1. RNA gel blot analysis indicated that, like the MIR1 promoter, the YER053C promoter is functional and that its activity varies according to aeration. An MIR1 gene null mutant did not grow on glycerol medium, whereas a YER053C null mutant grew well on the medium, suggesting that the YER053C gene is not essential for the mitochondrial function. YER053C also did not support the growth of the MIR1 null mutant on glycerol. The MIR1 and YER053C proteins were expressed in Escherichia coli and then reconstituted into liposomes. Unlike the proteoliposomes of MIR1, those of YER053C did not exhibit significant phosphate transport activity. Unexpectedly, it was shown that YER053C is localized in vacuoles, not mitochondria, by immunological electron microscopy. These results suggest that, during evolution, yeast lost the function and/or mitochondrial targeting of YER053C and then recruited an atypical MIR1 as the only transporter.

Copper Import into the Mitochondrial Matrix in Saccharomyces cerevisiae Is Mediated by Pic2, a Mitochondrial Carrier Family Protein

“…Pic2 has been previously implicated in phosphate transport in yeast, as multicopy PIC2 could reverse a mir1⌬pic2⌬ growth defect on a non-fermentable carbon source and rescue phosphate transport in mir1⌬pic2⌬ mitochondria as assayed by mitochondrial swelling (30,36). PIC2 has also been identified as a high copy suppressor of the mitochondrial K ϩ /H ϩ exchanger mutant (mdm38⌬) of yeast (37).…”

The involvement of mitochondrial phosphate transporter in accelerating bud dormancy release during chilling treatment of tree peony (Paeonia suffruticosa)

“…3). Interestingly, the MPT proteins, which were divided in plant or animal clade, all contained Cys residue, whereas MPT catalytic center of yeast contains Thr residue (Phelps et al 1991;Takabatake et al 2001), suggesting that the catalytic center in higher organisms contains the Cys residue instead of Thr residue, which might be the results of biological evolution. Moreover, it has been concluded that the activities of Cys residues are sensitive to N-ethylmaleimide (NEM) (Kolbe and Wohlrab 1985;Kaplan et al 1986), and the sensitivity of Cys residue in PsMPT to NEM needs to be studied or investigated further.…”

The mammalian phosphate carrier SLC25A3 is a mitochondrial copper transporter required for cytochrome c oxidase biogenesis

“…The closest homolog of Pic2 in mammals is SLC25A3 (49% identity and 65% similarity with Pic2). SLC25A3 is an established phosphate carrier in mammals, but in yeast Mir1 (41% identity and 61% similarity to SLC25A3; 40% identity and 59% similarity to Pic2) instead of Pic2 is the major phosphate transporter (21,22).…”