Rescue of Notch signaling in cells incapable of GDP-L-fucose synthesis by gap junction transfer of GDP-L-fucose in Drosophila. Kenjiroo Matsumoto¹, Tomonori Ayukawa², Ishikawa O. Hiroyuki³, Akira Ishio¹, Tomoko Yamakawa¹, Takuya Suzuki¹, Kenji Matsuno¹. 1) Biological Science, Osaka university, Toyonaka,Osaka, Japan; 2) Medical Science, Akita university, Toyonaka,Akita, Japan; 3) Science, Chiba university, Chiba,Chiba, Japan.

   Notch and its ligand interactions are essential for ligand dependent Notch signaling. Notch contains epidermal growth factor (EGF)-like repeats, many of which have O -fucose glycan modification that regulate Notch-ligand binding. This modification requires GDP-L-fucose as a donor of fucose. A possibility that GDP-L-fucose is supplied intercellraly was considered, however the molecular basis of GDP-L-fucose transportation have not been explored in depth. Here, our Drosophila study showed that GDP-L-fucose is supplied intercellularly through gap junctions in vivo (PNAS, 2012). Moreover, the gap junction-mediated supply of GDP-L-fucose was sufficient to support the fucosylation of Notch EGF-like repeats (PNAS, 2012).