H⁺ and Pi Byproducts of Glycosylation Affect Ca²⁺ Homeostasis and Are Retrieved from the Golgi Complex by Homologs of TMEM165 and XPR1.

ABSTRACT: Glycosylation reactions in the Golgi complex and the endoplasmic reticulum utilize nucleotide sugars as donors and produce inorganic phosphate (Pi) and acid (H⁺) as byproducts. Here we show that homologs of mammalian XPR1 and TMEM165 (termed Erd1 and Gdt1) recycle luminal Pi and exchange luminal H⁺ for cytoplasmic Ca²⁺, respectively, thereby promoting growth of yeast cells in low Pi and low Ca²⁺ environments. As expected for reversible H⁺/Ca²⁺ exchangers, Gdt1 also promoted growth in high Ca²⁺ environments when the Golgi-localized V-ATPase was operational but had the opposite effect when the V-ATPase was eliminated. Gdt1 activities were negatively regulated by calcineurin signaling and by Erd1, which recycled the

SUBMITTER: Snyder NA 

PROVIDER: S-EPMC5714488 | biostudies-literature | 2017 Dec

REPOSITORIES: biostudies-literature