Identification of a Post-translational Modification with Ribitol-Phosphate and Its Defect in Muscular Dystrophy

Autor: Motoi Kanagawa, Kazuhiro Kobayashi, Michiko Tajiri, Hiroshi Manya, Atsushi Kuga, Yoshiki Yamaguchi, Keiko Akasaka-Manya, Jun-ichi Furukawa, Mamoru Mizuno, Hiroko Kawakami, Yasuro Shinohara, Yoshinao Wada, Tamao Endo, Tatsushi Toda
Jazyk: angličtina
Rok vydání: 2016
Předmět:
Zdroj: Cell Reports, Vol 14, Iss 9, Pp 2209-2223 (2016)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2016.02.017
Popis: Glycosylation is an essential post-translational modification that underlies many biological processes and diseases. α-dystroglycan (α-DG) is a receptor for matrix and synaptic proteins that causes muscular dystrophy and lissencephaly upon its abnormal glycosylation (α-dystroglycanopathies). Here we identify the glycan unit ribitol 5-phosphate (Rbo5P), a phosphoric ester of pentose alcohol, in α-DG. Rbo5P forms a tandem repeat and functions as a scaffold for the formation of the ligand-binding moiety. We show that enzyme activities of three major α-dystroglycanopathy-causing proteins are involved in the synthesis of tandem Rbo5P. Isoprenoid synthase domain-containing (ISPD) is cytidine diphosphate ribitol (CDP-Rbo) synthase. Fukutin and fukutin-related protein are sequentially acting Rbo5P transferases that use CDP-Rbo. Consequently, Rbo5P glycosylation is defective in α-dystroglycanopathy models. Supplementation of CDP-Rbo to ISPD-deficient cells restored α-DG glycosylation. These findings establish the molecular basis of mammalian Rbo5P glycosylation and provide insight into pathogenesis and therapeutic strategies in α-DG-associated diseases.
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