Deficiency of Dol-P-Man Synthase Subunit DPM3 Bridges the Congenital Disorders of Glycosylation with the Dystroglycanopathies

Lefeber, Dirk J. and Schoenberger, Johannes and Morava, Eva and Guillard, Mailys and Huyben, Karin M. and Verriip, Kiek and Grafakou, Olga and Evangelioi, Athanasios and Preijers, Frank W. and Manta, Panagiota and Yildiz, Jef and Gruenewald, Stephanie and Spilioti, Martha and van den Elzen, Christa and Klein, Dominique and Hess, Daniel and Ashida, Hisashi and Hofsteenge, Jan and Maeda, Yusuke and van den Heuvel, Lambert and Lammens, Martin and Lehle, Ludwig and Wevers, Ron A. (2009) Deficiency of Dol-P-Man Synthase Subunit DPM3 Bridges the Congenital Disorders of Glycosylation with the Dystroglycanopathies. AMERICAN JOURNAL OF HUMAN GENETICS, 85 (1). pp. 76-86. ISSN 0002-9297, 1537-6605

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Abstract

Alpha-dystroglycanopathies such as Walker Warburg syndrome represent an important subgroup of the muscular dystrophies that have been related to defective O-mannosylation of alpha-dystroglycan. In many patients, the underlying genetic etiology remains unsolved. Isolated muscular dystrophy has not been described in the congenital disorders of glycosylation (CDG) caused by N-linked protein glycosylation defects. Here, we present a genetic N-glycosylation disorder with muscular dystrophy in the group of CDG type I. Extensive biochemical investigations revealed a strongly reduced dolichol-phosphate-mannose (Dol-P-Man) synthase activity. Sequencing of the three DPM subunits and complementation of DPM3-deficient CHO2.38 cells showed a pathogenic p.L85S missense mutation in the strongly conserved coiled-coil domain of DPM3 that tethers catalytic DPM1 to the ER membrane. Cotransfection experiments in CHO cells showed a reduced binding capacity of DPM3(L85S) for DPM1. Investigation of the four Dol-P-Man-dependent glycosylation pathways in the ER revealed strongly reduced O-mannosylation of alpha-dystroglycan in a muscle biopsy, thereby explaining the clinical phenotype of muscular dystrophy. This mild Dol-P-Man biosynthesis defect due to DPM3 mutations is a cause for alpha-dystroglycanopathy, thereby bridging the congenital disorders of glycosylation with the dystroglycanopathies.

Item Type: Article
Uncontrolled Keywords: DOLICHOL-PHOSPHATE-MANNOSE; N-LINKED GLYCOSYLATION; SACCHAROMYCES-CEREVISIAE; DEFECTIVE GLYCOSYLATION; GLYCOPROTEIN SYNDROME; MUSCULAR-DYSTROPHIES; MAMMALIAN-CELLS; BIOSYNTHESIS; PROTEIN; GENE;
Subjects: 500 Science > 580 Botanical sciences
Divisions: Biology, Preclinical Medicine > Institut für Pflanzenwissenschaften > Lehrstuhl für Zellbiologie und Pflanzenphysiologie (Prof. Dr. Klaus Grasser)
Depositing User: Dr. Gernot Deinzer
Date Deposited: 10 Sep 2020 10:20
Last Modified: 10 Sep 2020 10:20
URI: https://pred.uni-regensburg.de/id/eprint/28705

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