PMID: 21757702

 

    Legend: Gene, Sites

Title : O-glucose trisaccharide is present at high but variable stoichiometry at multiple sites on mouse Notch1

Abstract :
  1. Notch activity is regulated by both O-fucosylation and O-glucosylation, and Notch receptors contain multiple predicted sites for both
  2. Here we examine the occupancy of the predicted O-glucose sites on mouse Notch1 ( mN1 ) using the consensus sequence C(1) XSXPC(2)
  3. We show that all of the predicted sites are modified, although the efficiency of modifying O-glucose sites is site- and cell type-dependent
  4. For instance, although most sites are modified at high stoichiometries, the site at EGF 27 is only partially glucosylated, and the occupancy of the site at EGF 4 varies with cell type
  5. O-Glucose is also found at a novel, non-traditional consensus site at EGF 9
  6. Based on this finding, we propose a revision of the consensus sequence for O-glucosylation to allow alanine N-terminal to cysteine 2 : C(1) XSX(A/P) C(2)
  7. We also show through biochemical and mass spectral analyses that serine is the only hydroxyamino acid that is modified with O-glucose on EGF repeats
  8. The O-glucose at all sites is efficiently elongated to the trisaccharide Xyl-Xyl-Glc
  9. To establish the functional importance of individual O-glucose sites in mN1 , we used a cell-based signaling assay
  10. Elimination of most individual sites shows little or no effect on mN1 activation, suggesting that the major effects of O-glucose are mediated by modification of multiple sites
  11. Interestingly, elimination of the site in EGF 28, found in the Abruptex region of Notch , does significantly reduce activity
  12. These results demonstrate that, like O-fucose, the O-glucose modifications of EGF repeats occur extensively on mN1 , and they play important roles in Notch function
Output (sent_index, trigger, protein, sugar, site):
  • 2. sites, , -, mouse Notch1 (mN1) using the consensus sequence C(1)XSXPC(2), sequence C(1)
  • 4. occupancy, , -, -, site
  • 5. found, , -, O-Glucose, site
  • 7. modified, , -, O-glucose, serine
Output(Part-Of) (sent_index, protein, site):
  • 0. Notch1, sites
  • 1. Notch receptors, sites
  • 11. Notch, region
  • 2. Notch1, sequence C(1)
  • 4. EGF 4, site
  • 4. EGF, site
  • 5. EGF 9, site
*Output_Site_Fusion* (sent_index, protein, sugar, site):
  • 2. Notch1, mouse Notch1 (mN1) using the consensus sequence C(1)XSXPC(2), sequence C(1)

 

 

Protein NCBI ID SENTENCE INDEX
mN1 18128 2,9,10,12
Notch 18128 1,11,12
Notch receptors 18128 1