Interaction of the N-methyl-D-aspartate receptor complex with a novel synapse-associated protein, SAP102

Lit Fui Lau, Andrew Mammen, Michael D. Enters, Stefan Kindler, Wook Joon Chung, Craig C. Garner, Richard L. Huganirt

Research output: Contribution to journalArticlepeer-review

Abstract

Ionotropic glutamate receptors are known to cluster at high concentration on the postsynaptic membrane of excitatory synapses, but the mechanism by which this occurs is poorly understood. Studies on the neuromuscular junction and central inhibitory synapses suggest that clustering of neurotransmitter receptors requires its interaction with a cytoplasmic protein. Recently, in vitro studies have shown that members of the N-methylo-aspartate (NMDA) class of glutamate receptors interact with a synapse-associated protein, SAP90 (PSD-95). However, evidence for the in vivo interaction of MDA receptors with SAPs is still lacking. In the present study, we demonstrate the specific interaction between SAP102, a novel synapse-associated protein, and the NMDA receptor complex from the rat cortical synaptic plasma membranes using co-immunoprecipitation techniques. No association was observed between SAP102 and GluR1, a member of the α- amino-3-hydroxy-5-methyl-4-isoxazolepropionate class of glutamate receptors. To identify the domain on the NMDA receptor responsible for this interaction, we constructed hexahistidine fusion proteins from different regions of the NRla and NR2 subunits of the NMDA receptor. Immunoblot overlay experiments showed that while the C-terminal domain of the NR2 subunit displayed strong binding, the NRla intracellular C-terminal tail did not interact with SAP102. The site of interaction was more precisely located to the last 20 amino acids of the NR2 subunit as indicated by the interaction of the synthetic peptide with SAP102. In summary, we demonstrate here for the first time an in vivo interaction between the native NMDA receptor complex and a synapse-associated protein. These results suggest that SAP102 may play an important role in NMDA receptor clustering and immobilization at excitatory synapses.

Original languageEnglish (US)
Pages (from-to)21622-21628
Number of pages7
JournalJournal of Biological Chemistry
Volume271
Issue number35
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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