The extracellular N-terminal domain (NTD) is the largest region of NMDA receptors; however, biological roles for this ectodomain remain unknown. Here, we determined that the F-box protein, Fbx2, bound to high-mannose glycans of the NR1 ectodomain. F-box proteins specify ubiquitination by linking protein substrates to the terminal E3 ligase. Indeed, ubiquitination of NR1 was increased by Fbx2 an...

Functional NMDA receptors are heteromultimeric complexes of the NR1 subunit in combination with at least one of the four NR2 subunits (A-D). Coexpression of NR3A, an additional subunit of the NMDA receptor family, modifies NMDA-mediated responses. It is unclear whether NR3A interacts directly with NR1 and/or NR2 subunits and how such association might regulate the intracellular trafficking and ...

The relationship between four pharmacologically distinct NMDA receptor subtypes, identified in radioligand binding studies, and the recently identified NMDA receptor subunits (NR1a-g, NR2A-D) has not been determined. In this report, we demonstrate that the anatomical distribution of the four NMDA receptor subtypes strikingly parallels the distribution of mRNA encoding NR2A-D subunits. The distr...

Antagonists to the N-methyl-D-aspartate (NMDA) receptor bind to various extraneuronal tissues. We therefore assessed the expression of the main NMDA subunit, NR1, in various tissues. We demonstrate that NR1 appears to be most abundant in the rat kidney and heart. NR1 is present in total rat kidney, cortex, and medulla. Of the NR2 subunits, only the NR2C subunit protein is present in the kidney....

Although serine proteases and their receptors are best known for their role in blood coagulation and fibrinolysis, the CNS expresses many components of an extracellular protease signaling system including the protease-activated receptor-1 (PAR1), for which thrombin is the most effective activator. In this report we show that activation of PAR1 potentiates hippocampal NMDA receptor responses in ...

Functional and structural alterations of clustered postsynaptic ligand gated ion channels in neuronal cells are thought to contribute to synaptic plasticity and memory formation in the human brain. Here, we describe a novel molecular mechanism for structural alterations of NR1 subunits of the NMDA receptor. In cultured rat spinal cord neurons, chronic NMDA receptor stimulation induces disappear...

To determine the importance of the NMDA receptor (NMDAR) in pain hypersensitivity after injury, the NMDAR1 (NR1) subunit was selectively deleted in the lumbar spinal cord of adult mice by the localized injection of an adenoassociated virus expressing Cre recombinase into floxed NR1 mice. NR1 subunit mRNA and dendritic protein are reduced by 80% in the area of the virus injection, and NMDA curre...

NMDA receptors are excitatory neurotransmitter receptors critical for synaptic plasticity and neuronal development in the mammalian brain. These receptors are found highly concentrated in the postsynaptic membrane of glutamatergic synapses. To investigate the molecular mechanisms underlying NMDA receptor localization, we used the yeast two-hybrid system to identify proteins expressed in the bra...

Felbamate is an anticonvulsant used in the treatment of seizures associated with Lennox-Gastaut syndrome and complex partial seizures that are refractory to other medications. Its unique clinical profile is thought to be due to an interaction with N-methyl-D-aspartate (NMDA) receptors, resulting in decreased excitatory amino acid neurotransmission. To further characterize the interaction betwee...

Activation of N-methyl-D-aspartate-selective ionotropic glutamate receptors (NMDA receptors) requires two agonists, glutamate and glycine. These ligands are thought to bind to the NR2 and NR1 subunits, respectively, apparently ruling out the formation of functional homomeric receptors. However, NMDA-mediated currents are observed when the mammalian NR1 subunit is expressed alone in Xenopus laev...