O-Fucose Monosaccharide of Drosophila Notch Has a Temperature-sensitive Function and Cooperates with O-Glucose Glycan in Notch Transport and Notch Signaling Activation

Dual Roles of O-Glucose Glycans Redundant with Monosaccharide O-Fucose on Notch in Notch Trafficking

“…The following mutant alleles were used: O-fut1 R245A (19); the previously described sham-null allele shams 34 (13), the UDP-xylose synthase (Uxs)-null allele Uxs 1 (this study), the Uxs-deletion mutant Df(2R)BSC783 (Bloomington 27355) (20), and the rumi-null allele rumi 44 (12). The following UAS lines were used for RNA interference (RNAi): UAS-Notch inverted repeat (21) and UAS-peptide O-xylosyltransferase (Oxt) inverted repeat (21).…”

“…Recently, it was suggested that the monosaccharide O-fucose and the O-glucose trisaccharide function redundantly in Notch signaling, probably by promoting the proper folding of Notch (19). Defects associated with the simultaneous loss of these two modifications are far more severe than and qualitatively different from the loss of only one of the modifications (19).…”

“…The function of the monosaccharide O-fucose was previously unclear, because O-fut1 has dual functions: an O-fucosyltransferase function and a Notch-specific chaperone-like function apparently independent of its O-fucosyltransferase activity (18). However, it was recently found that the monosaccharide O-fucose is essential for Notch signaling at high temperatures (30°C) (19). Rumi adds O-glucose to a CXSX(P/A)C motif in the EGF-like repeats, and this modification is also essential for Notch activation (Fig.…”

“…Defects associated with the simultaneous loss of these two modifications are far more severe than and qualitatively different from the loss of only one of the modifications (19). How-* This work was supported by grants-in-aid from the Japanese Ministry of ever, the specific sugar moiety in the O-glucose trisaccharide that functions redundantly with O-fucose was previously unknown.…”

Super-resolution imaging in glycoscience: New developments and challenges

“…At the molecular level, carbohydrates in membrane proteins are known to modulate protein solubility, tra±cking, and signaling by a®ecting its folding, structure, and function. [1][2][3] In biological systems, carbohydrates also play vital roles in various physiological and pathological processes. The increasing¯ndings indicate that carbohydrates are involved in cell di®erentia-tion and development, cell adhesion and motility, recognition, signaling, and immune response.…”