Yeast Gdt1 is a Golgi-localized calcium transporter required for stress-induced calcium signaling and protein glycosylation

• Published in: Scientific reports 2016-04, Vol.6 (1), p.24282-24282, Article 24282
• Main Authors: Colinet, Anne-Sophie, Sengottaiyan, Palanivelu, Deschamps, Antoine, Colsoul, Marie-Lise, Thines, Louise, Demaegd, Didier, Duchêne, Marie-Clémence, Foulquier, François, Hols, Pascal, Morsomme, Pierre
• Format: Article
• Language: English
• Subjects: 631/80/221; 631/80/642/1525; Ca2+-transporting ATPase; Calcium; Calcium - metabolism; Calcium Channels - genetics; Calcium Channels - metabolism; Calcium influx; Calcium Signaling; Calcium signalling; Calcium transport; Carboxypeptidase C; Gene Expression; Glycosylation; Golgi apparatus; Humanities and Social Sciences; Lactococcus lactis; Lactococcus lactis - genetics; Lactococcus lactis - metabolism; multidisciplinary; Osmotic Pressure; Osmotic shock; Peptides; Proteins; Recombinant Proteins - genetics; Recombinant Proteins - metabolism; Saccharomyces cerevisiae; Saccharomyces cerevisiae - enzymology; Saccharomyces cerevisiae - genetics; Saccharomyces cerevisiae - metabolism; Saccharomyces cerevisiae - physiology; Saccharomyces cerevisiae Proteins - genetics; Saccharomyces cerevisiae Proteins - metabolism; Science; Yeast; Yeasts
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep24282

Calcium signaling depends on a tightly regulated set of pumps, exchangers and channels that are responsible for controlling calcium fluxes between the different subcellular compartments of the eukaryotic cell. We have recently reported that two members of the highly-conserved UPF0016 family, human TMEM165 and budding yeast Gdt1p, are functionally related and might form a new group of Golgi-localized cation/Ca 2+ exchangers. Defects in the human protein TMEM165 are known to cause a subtype of Congenital Disorders of Glycosylation. Using an assay based on the heterologous expression of GDT1 in the bacterium Lactococcus lactis , we demonstrated the calcium transport activity of Gdt1p. We observed a Ca 2+ uptake activity in cells expressing GDT1 , which was dependent on the external pH, indicating that Gdt1p may act as a Ca 2+ /H + antiporter. In yeast, we found that Gdt1p controls cellular calcium stores and plays a major role in the calcium response induced by osmotic shock when the Golgi calcium pump, Pmr1p, is absent. Importantly, we also discovered that, in the presence of a high concentration of external calcium, Gdt1p is required for glycosylation of carboxypeptidase Y and the glucanosyltransferase Gas1p. Finally we showed that glycosylation process is restored by providing more Mn 2+ to the cells.