The yeast Gdt1 protein mediates the exchange of H+ for Ca2+ and Mn2+ influencing the Golgi pH
(2023) Journal of Biological Chemistry — Vol. 299, n° 5, p. 104628 (2023)
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Stribny, Jiri 
- Abstract
- The GDT1 family is broadly spread and highly conserved among living organisms. GDT1 members have functions in key processes like glycosylation in humans and yeasts and photo-synthesis in plants. These functions are mediated by their ability to transport ions. While transport of Ca2+ or Mn2+ is well established for several GDT1 members, their transport mechanism is poorly understood. Here, we demonstrate that H + ions are transported in exchange for Ca 2+ and Mn 2+ cations by the Golgi-localized yeast Gdt1 protein. We performed direct transport measurement across a biological membrane by expressing Gdt1p in Lactococcus lactis bacterial cells and by recording either the extracellular pH or the intracellular pH during the application of Ca2+ , Mn2+ or H + gradients. Besides, in vivo cytosolic and Golgi pH measurements were performed in Saccharomyces cerevisiae with genetically encoded pH probes targeted to those subcellular compartments. These data point out that the flow of H + ions carried by Gdt1p could be reversed according to the physiological conditions. Together, our experiments unravel the influence of the relative concentration gradients for Gdt1p-mediated H + transport and pave the way to decipher the regulatory mechanisms driving the activity of GDT1 orthologs in various biological contexts.
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Citations
Deschamps, A., Thines, L., Colinet, A.-S., Stribny, J., & Morsomme, P. (2023). The yeast Gdt1 protein mediates the exchange of H+ for Ca2+ and Mn2+ influencing the Golgi pH. Journal of Biological Chemistry, 299(5), 104628. https://doi.org/10.1016/j.jbc.2023.104628 (Original work published 2023)