Gert Matthijs, Valérie Decool, Sven Potelle, Marine Houdou, Eudoxie Dulary, Sandrine Duvet, Yann Guérardel, François Foulquier, Marie-Ange Krzewinski-Recchi, Shin-Yi Yu, Geoffroy de Bettignies, Anne Garat, Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Centre de recherches de biochimie macromoléculaire (CRBM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-IFR122-Centre National de la Recherche Scientifique (CNRS), Variabilité génétique des défenses de l'organisme face à son environnement chimique, PRES Université Lille Nord de France-Université de Lille, Droit et Santé, Molecular Diagnostics, Center for Human Genetics, Gasthuisberg, Katholieke Universiteit Leuven and Flanders Interuniversity Institute for Biotechnology 4, Leuven, Belgium, Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre de recherche en Biologie cellulaire de Montpellier (CRBM), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ANR-15-CE14-0001,SOLV_CDG,Décryptage des patients CDG (Congenital Disorders of Glyvosylation) déficients en TMEM165 - de la compréhension des mécanismes moléculaires à une thérapie(2015), ANR-15-RAR3-0004,EURO-CDG-2,A European research network directed towards improving diagnosis and treatment of inborn glycosylation disorders.(2015), European Project: 643578,H2020,H2020-HCO-2014,E-Rare-3(2014), Institut National de la Recherche Agronomique (INRA)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre de recherche en Biologie Cellulaire (CRBM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Inserm, Université de Lille, CHU Lille, Institut Pasteur de Lille, CNRS, IMPact de l'Environnement Chimique sur la Santé humaine (IMPECS) - EA 4483, IMPact de l’Environnement Chimique sur la Santé humaine (IMPECS) - EA 4483, Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 [UGSF], Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 [UGSF], Impact de l'environnement chimique sur la santé humaine - ULR 4483 [IMPECS], and Center for Human Genetics, University of Leuven School of Medicine
The Golgi ion homeostasis is tightly regulated to ensure essential cellular processes such as glycosylation, yet our understanding of this regulation remains incomplete. Gdt1p is a member of the conserved Uncharacterized Protein Family (UPF0016). Our previous work suggested that Gdt1p may function in the Golgi by regulating Golgi Ca(2+)/Mn(2+) homeostasis. NMR structural analysis of the polymannan chains isolated from yeasts showed that the gdt1Δ mutant cultured in presence of high Ca(2+) concentration, as well as the pmr1Δ and gdt1Δ/pmr1Δ strains presented strong late Golgi glycosylation defects with a lack of α-1,2 mannoses substitution and α-1,3 mannoses termination. The addition of Mn(2+) confirmed the rescue of these defects. Interestingly, our structural data confirmed that the glycosylation defect in pmr1Δ could also completely be suppressed by the addition of Ca(2+). The use of Pmr1p mutants either defective for Ca(2+) or Mn(2+) transport or both revealed that the suppression of the observed glycosylation defect in pmr1Δ strains by the intraluminal Golgi Ca(2+) requires the activity of Gdt1p. These data support the hypothesis that Gdt1p, in order to sustain the Golgi glycosylation process, imports Mn(2+) inside the Golgi lumen when Pmr1p exclusively transports Ca(2+). Our results also reinforce the functional link between Gdt1p and Pmr1p as we highlighted that Gdt1p was a Mn(2+) sensitive protein whose abundance was directly dependent on the nature of the ion transported by Pmr1p. Finally, this study demonstrated that the aspartic residues of the two conserved motifs E-x-G-D-[KR], likely constituting the cation binding sites of Gdt1p, play a crucial role in Golgi glycosylation and hence in Mn(2+)/Ca(2+)transport. ispartof: Biochimica et Biophysica Acta vol:1862 issue:3 pages:394-402 ispartof: location:Netherlands status: published