Two pathways for importing GDP-fucose into the endoplasmic reticulum lumen function redundantly in the O-fucosylation of Notch in Drosophila.
Notch is a transmembrane receptor that shares homology with proteins containing epidermal growth factor-like repeats and mediates the cell-cell interactions necessary for many cell fate decisions. In Drosophila, O-fucosyltransferase 1 catalyzes the O-fucosylation of these epidermal growth factor-like repeats. This O-fucose elongates, resulting in an O-linked tetrasaccharide that regulates the signaling activities of Notch. Fucosyltransferases utilize GDP-fucose, which is synthesized in the cytosol, but fucosylation occurs in the lumen of the endoplasmic reticulum (ER) and Golgi. Therefore, GDP-fucose uptake into the ER and Golgi is essential for fucosylation. However, although GDP-fucose biosynthesis is well understood, the mechanisms and intracellular routes of GDP-fucose transportation remain unclear. Our previous study on the Drosophila Golgi GDP-fucose transporter (Gfr), which specifically localizes to the Golgi, suggested that another GDP-fucose transporter(s) exists in Drosophila. Here, we identified Efr (ER GDP-fucose transporter), a GDP-fucose transporter that localizes specifically to the ER. Efr is a multifunctional nucleotide sugar transporter involved in the biosynthesis of heparan sulfate-glycosaminoglycan chains and the O-fucosylation of Notch. Comparison of the fucosylation defects in the N-glycans in Gfr and Efr mutants revealed that Gfr and Efr made distinct contributions to this modification; Gfr but not Efr was crucial for the fucosylation of N-glycans. We also found that Gfr and Efr function redundantly in the O-fucosylation of Notch, although they had different localizations and nucleotide sugar transportation specificities. These results indicate that two pathways for the nucleotide sugar supply, involving two nucleotide sugar transporters with distinct characteristics and distributions, contribute to the O-fucosylation of Notch.
Ishikawa
Hiroyuki O
HO
From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510.
Ayukawa
Tomonori
T
the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510.
Nakayama
Minoru
M
From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510.
Higashi
Shunsuke
S
the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510.
Kamiyama
Shin
S
the Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, and.
Nishihara
Shoko
S
the Department of Bioinformatics, Soka University, 1-236 Tangi-cho, Hachioji, Tokyo 192-8577, and.
Aoki
Kazuhisa
K
the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan.
Ishida
Nobuhiro
N
the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan.
Sanai
Yutaka
Y
the Department of Biochemical Cell Research, Tokyo Metropolitan Institute of Medical Science, 3-18-22 Honkomagome, Bunkyo-ku, Tokyo 113-8613, Japan.
Matsuno
Kenji
K
From the Genome and Drug Research Center, Research Institute for Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510; the Department of Biological Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510. Electronic address: matsuno@rs.noda.tus.ac.jp.
D000818:Animals; D001692:Biological Transport; D015153:Blotting, Western; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000096:biosynthesis; D006031:Glycosylation; D006056:Golgi Apparatus / Q000378:metabolism; D006154:Guanosine Diphosphate Fucose / Q000378:metabolism*; D007150:Immunohistochemistry; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D033704:Nucleotide Transport Proteins / Q000235:genetics / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
D029721:Drosophila Proteins; C547522:Efr protein, Drosophila; D006025:Glycosaminoglycans; D009004:Monosaccharide Transport Proteins; C497759:N protein, Drosophila; D033704:Nucleotide Transport Proteins; D011134:Polysaccharides; D051880:Receptors, Notch; C494581:nac protein, Drosophila; D006154:Guanosine Diphosphate Fucose