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Updated: Nov 17, 2025

Assessment of Submitochondrial Protein Localization in Budding Yeast Saccharomyces cerevisiae
Published on: July 19, 2021
Mitochondrial copper and phosphate transporter specificity was defined early in the evolution of eukaryotes
Xinyu Zhu1, Aren Boulet2, Katherine M Buckley1
1Department of Biological Sciences, Auburn University, Auburn, United States.
Abstract:
The mitochondrial carrier family protein SLC25A3 transports both copper and phosphate in mammals, yet in Saccharomyces cerevisiae the transport of these substrates is partitioned across two paralogs: PIC2 and MIR1. To understand the ancestral state of copper and phosphate transport in mitochondria, we explored the evolutionary relationships of PIC2 and MIR1 orthologs across the eukaryotic tree of life. Phylogenetic analyses revealed that PIC2-like and MIR1-like orthologs are present in all major eukaryotic supergroups, indicating an ancient gene duplication created these paralogs. To link this phylogenetic signal to protein function, we used structural modeling and site-directed mutagenesis to identify residues involved in copper and phosphate transport. Based on these analyses, we generated an L175A variant of mouse SLC25A3 that retains the ability to transport copper but not phosphate. This work highlights the utility of using an evolutionary framework to uncover amino acids involved in substrate recognition by mitochondrial carrier family proteins.
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