title: Yeast Gdt1 is a Golgi-localized calcium transporter required for stress-induced calcium signaling and protein glycosylation.
abstract: 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.
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Colinet
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Palanivelu
authors.initials: P
authors.lastname: Sengottaiyan
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Antoine
authors.initials: A
authors.lastname: Deschamps
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Marie-Lise
authors.initials: ML
authors.lastname: Colsoul
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Louise
authors.initials: L
authors.lastname: Thines
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Didier
authors.initials: D
authors.lastname: Demaegd
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Marie-Clémence
authors.initials: MC
authors.lastname: Duchêne
authors.affiliation: UMR8576 CNRS, Structural and Functional Glycobiology Unit, University of Lille 1, IFR 114, F-59655 Villeneuve D'Ascq, France.
authors.forename: François
authors.initials: F
authors.lastname: Foulquier
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Pascal
authors.initials: P
authors.lastname: Hols
authors.affiliation: Institut des Sciences de la Vie, Université catholique de Louvain, B-1348 Louvain-la-Neuve, Belgium.
authors.forename: Pierre
authors.initials: P
authors.lastname: Morsomme
mesh_terms: D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000235:genetics / Q000378:metabolism*; D020013:Calcium Signaling; D015870:Gene Expression; D006031:Glycosylation; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism; D009997:Osmotic Pressure; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D015220:Calcium Channels; D011994:Recombinant Proteins; D029701:Saccharomyces cerevisiae Proteins; C000614526:ribosome biosynthesis protein GDT1, S cerevisiae; D002118:Calcium