PMID: 12603841

 

    Legend: Gene, Sites

Title : Characterization of the functional role of the N-glycans in the AMPA receptor ligand-binding domain

Abstract :
  1. The ligand-binding domains of AMPA receptor subunits carry two conserved N-glycosylation sites
  2. In order to gain insight into the functional role of the corresponding N-glycans, we examined how the elimination of glycosylation at these sites ( N407 and N414 ) affects the ligand-binding characteristics, structural stability, cell-surface expression, and channel properties of homomeric GluR-D ( GluR4 ) receptor and its soluble ligand-binding domain (S1S2)
  3. GluR-D S1S2 S1S2 protein expressed as a secreted protein in insect cells was found to be glycosylated at N407 and N414
  4. No major differences in the ligand-binding properties were observed between the 'wild-type' S1S2 and non-glycosylated N407D/N414Q double mutant, or between S1S2 proteins expressed in the presence or absence of tunicamycin , an inhibitor of N-glycosylation
  5. Purified glycosylated and non-glycosylated S1S2 proteins also showed similar thermostabilities as determined by CD spectroscopy
  6. Full-length homomeric GluR-D receptor with N407D/N414Q mutation was expressed on the surface of HEK293 cells like the wild-type GluR-D
  7. In outside-out patches, GluR-D and the N407D/N414Q mutant produced similar rapidly desensitizing current responses to glutamate and AMPA
  8. We therefore report that the two conserved ligand-binding domain glycans do not play any major role in receptor-ligand interactions, do not impart a stabilizing effect on the ligand-binding domain , and are not critical for the formation and surface localization of homomeric GluR-D AMPA receptors in HEK293 cells
Output (sent_index, trigger, protein, sugar, site):
  • 1. N-glycosylation, , -, -, sites
  • 2. sites, , -, -, N407 and N414
  • 2. sites, , -, -, sites
  • 3. glycosylated, , -, -, N407 and N414
  • 3. glycosylated, , protein, -, N407 and N414
  • 5. glycosylated, , proteins, -, -
  • 5. non-glycosylated, , proteins, -, -
  • 8. domain, , -, the two conserved ligand-binding domain glycans, -
Output(Part-Of) (sent_index, protein, site):
  • 0. AMPA receptor, domain
  • 1. AMPA receptor subunits, domains
  • 1. AMPA receptor subunits, sites
*Output_Site_Fusion* (sent_index, protein, sugar, site):
  • 2. AMPA receptor, -, N407 and N414
  • 3. AMPA receptor, -, N407 and N414
  • 3. protein, -, N407 and N414

 

 

Protein NCBI ID SENTENCE INDEX