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A critical role of the N-methyl-D-aspartate (NMDA) receptor subunit (NR) 2A in the expression of redox sensitivity of NR1/NR2A recombinant NMDA receptors.
J Pharmacol Exp Ther. 1999 Nov; 291(2):785-92.JP

Abstract

In recombinant N-methyl-D-aspartate (NMDA) receptors, two redox modulatory sites are thought to exist, one formed by Cys744 and Cys798 on NMDA receptor subunit (NR) 1, and a second one, not yet localized, on NR2A. Reductants increase the open dwell-time and opening frequency of NR1/NR2A channels. In contrast, NR1/NR2B and NR1/NR2C channels exhibit changes only in opening frequency after redox treatments. Here, we evaluated whether the two redox sites act independently of each other, with the NR1 site affecting the opening frequency and the NR2A site altering open dwell-time. Unitary and whole-cell currents mediated by NMDA receptors composed of a cysteine-mutated NR1 subunit, NR1(C744A, C798A) were thus investigated. Dithiothreitol increased the open dwell-time and opening frequency of NR1(C744A, C798A)/NR2A receptors in a manner indistinguishable from that previously seen in wild-type channels. Marginal redox-induced changes in opening frequency of NR1(C744A, C798A)/NR2B receptors were noted. Redox modulation was completely abolished in NR1(C744A, C798A)/NR2C channels. Whole-cell recordings confirmed the single-channel results. Sulfhydryl reagents modulated NR1(C744A, C798A)/NR2A receptors identically to wild-type NR1/NR2A channels, whereas NR1(C744A, C798A)/NR2C receptors were insensitive to redox modulation. The oxidant 5,5'-dithio-bis-(2-nitrobenzoate) attenuated NR1(C744A, C798A)/NR2B receptor-mediated responses in a dithiothreitol-reversible manner. We conclude that cysteines 744 and 798 on the NR1 subunit are not involved in the redox modulation of NR1/NR2A receptors, but are crucial for the modulation of NR1/NR2C-containing receptors. This suggests that the NR2A subunit is necessary and sufficient for the expression of redox sensitivity in NR1/NR2A channels. The slight, but measurable residual redox sensitivity of the mutant NR1(C744A, C798A)/NR2B receptors suggests the existence of an additional redox-sensitive site on NR2B.

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Publisher Full Text

Authors+Show Affiliations

Brimecombe JC
Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA.
Potthoff WK
No affiliation info available
Aizenman E
No affiliation info available

MeSH

AnimalsBinding SitesCHO CellsCricetinaeCysteineDithionitrobenzoic AcidMutationOxidation-ReductionReceptors, N-Methyl-D-AspartateRecombinant ProteinsReducing AgentsSulfhydryl ReagentsTime FactorsTransfection

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

10525101

Citation

Brimecombe, J C., et al. "A Critical Role of the N-methyl-D-aspartate (NMDA) Receptor Subunit (NR) 2A in the Expression of Redox Sensitivity of NR1/NR2A Recombinant NMDA Receptors." The Journal of Pharmacology and Experimental Therapeutics, vol. 291, no. 2, 1999, pp. 785-92.
Brimecombe JC, Potthoff WK, Aizenman E. A critical role of the N-methyl-D-aspartate (NMDA) receptor subunit (NR) 2A in the expression of redox sensitivity of NR1/NR2A recombinant NMDA receptors. J Pharmacol Exp Ther. 1999;291(2):785-92.
Brimecombe, J. C., Potthoff, W. K., & Aizenman, E. (1999). A critical role of the N-methyl-D-aspartate (NMDA) receptor subunit (NR) 2A in the expression of redox sensitivity of NR1/NR2A recombinant NMDA receptors. The Journal of Pharmacology and Experimental Therapeutics, 291(2), 785-92.
Brimecombe JC, Potthoff WK, Aizenman E. A Critical Role of the N-methyl-D-aspartate (NMDA) Receptor Subunit (NR) 2A in the Expression of Redox Sensitivity of NR1/NR2A Recombinant NMDA Receptors. J Pharmacol Exp Ther. 1999;291(2):785-92. PubMed PMID: 10525101.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - A critical role of the N-methyl-D-aspartate (NMDA) receptor subunit (NR) 2A in the expression of redox sensitivity of NR1/NR2A recombinant NMDA receptors. AU - Brimecombe,J C, AU - Potthoff,W K, AU - Aizenman,E, PY - 1999/10/19/pubmed PY - 1999/10/19/medline PY - 1999/10/19/entrez SP - 785 EP - 92 JF - The Journal of pharmacology and experimental therapeutics JO - J Pharmacol Exp Ther VL - 291 IS - 2 N2 - In recombinant N-methyl-D-aspartate (NMDA) receptors, two redox modulatory sites are thought to exist, one formed by Cys744 and Cys798 on NMDA receptor subunit (NR) 1, and a second one, not yet localized, on NR2A. Reductants increase the open dwell-time and opening frequency of NR1/NR2A channels. In contrast, NR1/NR2B and NR1/NR2C channels exhibit changes only in opening frequency after redox treatments. Here, we evaluated whether the two redox sites act independently of each other, with the NR1 site affecting the opening frequency and the NR2A site altering open dwell-time. Unitary and whole-cell currents mediated by NMDA receptors composed of a cysteine-mutated NR1 subunit, NR1(C744A, C798A) were thus investigated. Dithiothreitol increased the open dwell-time and opening frequency of NR1(C744A, C798A)/NR2A receptors in a manner indistinguishable from that previously seen in wild-type channels. Marginal redox-induced changes in opening frequency of NR1(C744A, C798A)/NR2B receptors were noted. Redox modulation was completely abolished in NR1(C744A, C798A)/NR2C channels. Whole-cell recordings confirmed the single-channel results. Sulfhydryl reagents modulated NR1(C744A, C798A)/NR2A receptors identically to wild-type NR1/NR2A channels, whereas NR1(C744A, C798A)/NR2C receptors were insensitive to redox modulation. The oxidant 5,5'-dithio-bis-(2-nitrobenzoate) attenuated NR1(C744A, C798A)/NR2B receptor-mediated responses in a dithiothreitol-reversible manner. We conclude that cysteines 744 and 798 on the NR1 subunit are not involved in the redox modulation of NR1/NR2A receptors, but are crucial for the modulation of NR1/NR2C-containing receptors. This suggests that the NR2A subunit is necessary and sufficient for the expression of redox sensitivity in NR1/NR2A channels. The slight, but measurable residual redox sensitivity of the mutant NR1(C744A, C798A)/NR2B receptors suggests the existence of an additional redox-sensitive site on NR2B. SN - 0022-3565 UR - https://www.unboundmedicine.com/medline/citation/10525101/A_critical_role_of_the_N_methyl_D_aspartate__NMDA__receptor_subunit__NR__2A_in_the_expression_of_redox_sensitivity_of_NR1/NR2A_recombinant_NMDA_receptors_ L2 - https://jpet.aspetjournals.org/cgi/pmidlookup?view=long&pmid=10525101 DB - PRIME DP - Unbound Medicine ER -