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第１日　５月１８日（水）　16:05～16:25　A会場（オービットホール）

1A-O1-1605　　PDF

質量分析が明らかにしたリビトールリン酸を含むαジストログリカンの糖鎖構造

(¹大阪母子センター・ ²神戸大院医・ ³都健康長寿医セ研・ ⁴理研・ ⁵北大院先端生命・ ⁶野口研)
^o田尻道子¹・ 金川基²・ 小林千浩²・ 萬谷博³・ 久我敦²・ 山口芳樹⁴・ 赤阪啓子³・ 古川潤一⁵・ 水野真盛⁶・ 川上宏子⁶・ 篠原康郎⁵・ 遠藤玉夫³・ 戸田達史²・ 和田芳直¹

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 identified the previously unknown 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 found the enzyme activities of three major α-dystroglycanopathy-causing proteins to be 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.