title: A Temperature-sensitive mutation in the Arabidopsis thaliana phosphomannomutase gene disrupts protein glycosylation and triggers cell death.
abstract: Eukaryotic phosphomannomutases (PMMs) catalyze the interconversion of mannose 6-phosphate to mannose 1-phosphate and are essential to the biosynthesis of GDP-mannose. As such, plant PMMs are involved in ascorbic acid (AsA) biosynthesis and N-glycosylation. We report on the conditional phenotype of the temperature-sensitive Arabidopsis thaliana pmm-12 mutant. Mutant seedlings were phenotypically similar to wild type seedlings when grown at 16-18 degrees C but died within several days after transfer to 28 degrees C. This phenotype was observed throughout both vegetative and reproductive development. Protein extracts derived from pmm-12 plants had lower PMM protein and enzyme activity levels. In vitro biochemical analysis of recombinant proteins showed that the mutant PMM protein was compromised in its catalytic efficiency (K cat/K m). Despite significantly decreased AsA levels in pmm-12 plants, AsA deficiency could not account for the observed phenotype. Since, at restrictive temperature, total glycoprotein patterns were altered and glycosylation of protein-disulfide isomerase was perturbed, we propose that a deficiency in protein glycosylation is responsible for the observed cell death phenotype.
authors: Department of Plant Systems Biology, Flanders Institute for Biotechnology (VIB), Ghent University, 9052 Gent, Belgium.
authors: Frank A
authors: FA
authors: Hoeberichts
authors: Elke
authors: E
authors: Vaeck
authors: Guy
authors: G
authors: Kiddle
authors: Emmy
authors: E
authors: Coppens
authors: Brigitte
authors: B
authors: van de Cotte
authors: Antoine
authors: A
authors: Adamantidis
authors: Sandra
authors: S
authors: Ormenese
authors: Christine H
authors: CH
authors: Foyer
authors: Marc
authors: M
authors: Zabeau
authors: Dirk
authors: D
authors: Inzé
authors: Claire
authors: C
authors: Périlleux
authors: Frank
authors: F
authors: Van Breusegem
authors: Marnik
authors: M
authors: Vuylsteke
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D001205:Ascorbic Acid / Q000096:biosynthesis / Q000235:genetics; D002384:Catalysis; D016923:Cell Death / Q000235:genetics; D006023:Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D006031:Glycosylation; D006155:Guanosine Diphosphate Mannose / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature; D008360:Mannosephosphates / Q000096:biosynthesis / Q000235:genetics; D009154:Mutation; D010641:Phenotype; D017875:Phosphotransferases (Phosphomutases) / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D019704:Protein Disulfide-Isomerases / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000201:enzymology / Q000235:genetics
chemical_list: D006023:Glycoproteins; D008360:Mannosephosphates; D010940:Plant Proteins; D011994:Recombinant Proteins; C047217:mannose 1-phosphate; D006155:Guanosine Diphosphate Mannose; D019704:Protein Disulfide-Isomerases; D017875:Phosphotransferases (Phosphomutases); C052799:phosphomannomutase; D001205:Ascorbic Acid