Mitochondrial copper and phosphate transporter specificity was defined early in the evolution of eukaryotes
- Auburn University, United States
- University of Saskatchewan, Canada
- University Saskatchewan, Canada
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 modelling and site-directed mutagenesis to identify residues involved in copper and phosphate transport. Based on these analyses, we generated a 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.
Data availability
All data generated or analyzed during this study are included in the manuscript, supplemental file, and available on GenBank.
Article and author information
Author details
Funding
National Institutes of Health (R01GM120211)
- Scot C Leary
- Paul A Cobine
National Science Foundation (EF 2021886)
- Katherine M Buckley
Alabama Agricultural Experiment Station
- Paul A Cobine
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Zhu et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Mitochondrial copper and phosphate transporter specificity was defined early in the evolution of eukaryotes
eLife 10:e64690.
https://doi.org/10.7554/eLife.64690
Further reading
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- Biochemistry and Chemical Biology
- Microbiology and Infectious Disease
Teichoic acids (TA) are linear phospho-saccharidic polymers and important constituents of the cell envelope of Gram-positive bacteria, either bound to the peptidoglycan as wall teichoic acids (WTA) or to the membrane as lipoteichoic acids (LTA). The composition of TA varies greatly but the presence of both WTA and LTA is highly conserved, hinting at an underlying fundamental function that is distinct from their specific roles in diverse organisms. We report the observation of a periplasmic space in Streptococcus pneumoniae by cryo-electron microscopy of vitreous sections. The thickness and appearance of this region change upon deletion of genes involved in the attachment of TA, supporting their role in the maintenance of a periplasmic space in Gram-positive bacteria as a possible universal function. Consequences of these mutations were further examined by super-resolved microscopy, following metabolic labeling and fluorophore coupling by click chemistry. This novel labeling method also enabled in-gel analysis of cell fractions. With this approach, we were able to titrate the actual amount of TA per cell and to determine the ratio of WTA to LTA. In addition, we followed the change of TA length during growth phases, and discovered that a mutant devoid of LTA accumulates the membrane-bound polymerized TA precursor.
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- Biochemistry and Chemical Biology
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