PMID: 11439087

 

    Legend: Gene, Sites

Title : Site-directed removal of N-glycosylation sites in BST-1 / CD157 : effects on molecular and functional heterogeneity

Abstract :
  1. Cyclic ADP ribose (cADPR) is a novel second messenger that releases calcium from intracellular calcium stores, but works independently of inositol 1,4,5-trisphosphate
  2. In mammals ADP-ribosyl cyclase function is found in two membrane proteins , CD38 and bone marrow stromal cell antigen 1 ( BST-1 )/ CD157
  3. These enzymes are exposed extracellularly and also possess cADPR hydrolase activity, but an intracellular soluble ADP-ribosyl cyclase has been reported in human T-cells
  4. Previously, a soluble form of BST-1 / CD157 ( sBST-1 ), which lacked the glycosylphosphatidylinositol-anchored portion, was expressed by a baculovirus-insect-cell system
  5. In this study, we have purified the sBST-1 , and it migrated as two major bands by SDS /PAGE, suggesting that it is post-translationally modified
  6. BST-1 contains four putative N-glycosylation sites
  7. Tunicamycin treatment reduced sBST-1 expression in the culture medium, indicating that N-glycosylation is essential for secretion
  8. Site-directed mutagenesis was performed to generate sBST-1 mutants (N1-N4), each preserving a single N-glycosylation site
  9. N1, N3 and N4 were well secreted into the medium, and were each detected as a single band
  10. Although N3 and N4 retained the ADP-ribosyl cyclase activity, the cADPR-hydrolase activity was retained only in N4
  11. We conclude that N-glycosylation of sBST-1 facilitates the folding of the nascent polypeptide chain into a conformation that is conductive for intracellular transport and enzymic activity
  12. Furthermore a crystal has been obtained using the N4 mutant, but not the wild-type sBST-1
  13. Thus the artificial engineering of N-glycosylation sites could be an effective method to generate homogeneous material for structural studies
Output (sent_index, trigger, protein, sugar, site):
  • 0. N-glycosylation, , -, -, sites
  • 11. N-glycosylation, , sBST-1, -, -
  • 13. N-glycosylation, , -, -, sites
  • 6. N-glycosylation, , -, -, sites
  • 8. N-glycosylation, , -, -, site
Output(Part-Of) (sent_index, protein, site):
  • 6. BST-1, sites
  • 8. sBST-1, N1-N4
*Output_Site_Fusion* (sent_index, protein, sugar, site):

 

 

Protein NCBI ID SENTENCE INDEX
BST-1 683 0,2,6
CD38 952 2
form of BST-1 683 4
CD157 683 0,2,4