The Integrity of the Glycine Co-agonist Binding Site of N-Methyl-d-aspartate Receptors Is a Functional Quality Control Checkpoint for Cell Surface Delivery

摘要: Abstract N-Methyl-d-aspartate receptors are a subclass of ligand-gated, heteromeric glutamatergic neurotransmitter whose cell surface expression is regulated by quality control mechanisms. Functional checkpoints known to contribute trafficking non-N-methyl-d-aspartate glutamate receptors. Here we investigated if similar mechanisms operate for the delivery NMDA Point mutations in glycine binding domain NR1-1a subunit were generated: D732A, mutation that results an ∼3 × 104 decrease affinity; D732E, conservative change; and D723A, residue same has no effect on affinity. Each was co-expressed with NR2A mammalian cells. Immunoblotting immunoprecipitations showed all mutants expressed levels as wild-type associated NR2A. Cell measured enzyme-linked immunosorbent assay found whereas (D732E)/NR2A (D723A)/NR2A trafficked efficiently NR1-1a/NR2A, there 90% (D732A)/NR2A. This confirmed confocal microscopy imaging biotinylation. Further (D732A) co-transfected co-localized endoplasmic reticulum marker. Dichlorokynurenic acid, competitive site antagonist, partially rescued expression. Mutation ER retention motif ligand checkpoint early event preceding sorting These findings demonstrate integrity co-agonist functional requisite efficient assembled