title: Inactivation of NMDA receptors by direct interaction of calmodulin with the NR1 subunit.
abstract: NMDA (N-methyl-D-aspartate) receptors are excitatory neurotransmitter receptors in the brain critical for synaptic plasticity and neuronal development. These receptors are Ca2+-permeable glutamate-gated ion channels whose physiological properties are regulated by intracellular Ca2+. We report here the purification of a 20 kDa protein identified as calmodulin that interacts with the NR1 subunit of the NMDA receptor. Calmodulin binding to the NR1 subunit is Ca2+ dependent and occurs with homomeric NR1 complexes, heteromeric NR1/NR2 subunit complexes, and NMDA receptors from brain. Furthermore, calmodulin binding to NR1 causes a 4-fold reduction in NMDA channel open probability. These results demonstrate that NMDA receptor function can be regulated by direct binding of calmodulin to the NR1 subunit, and suggest a possible mechanism for activity-dependent feedback inhibition and Ca2+-dependent inactivation of NMDA receptors.
authors.affiliation: Department of Neuroscience, Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Ehlers
authors.forename: S
authors.initials: S
authors.lastname: Zhang
authors.forename: J P
authors.initials: JP
authors.lastname: Bernhadt
authors.forename: R L
authors.initials: RL
authors.lastname: Huganir
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002118:Calcium / Q000494:pharmacology; D002147:Calmodulin / Q000378:metabolism* / Q000494:pharmacology*; D002460:Cell Line; D002540:Cerebral Cortex / Q000378:metabolism*; D004533:Egtazic Acid; D006801:Humans; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism; D014162:Transfection
chemical_list: D002147:Calmodulin; D007473:Ion Channels; D046911:Macromolecular Substances; D009838:Oligodeoxyribonucleotides; D010446:Peptide Fragments; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D004533:Egtazic Acid; D002118:Calcium