A site in the fourth membrane-associated domain of the N-methyl-D-aspartate receptor regulates desensitization and ion channel gating

被引:51
作者
Ren, H [1 ]
Honse, Y [1 ]
Karp, BJ [1 ]
Lipsky, RH [1 ]
Peoples, RW [1 ]
机构
[1] NIAAA, Unit Cellular Neuropharmacol, LMCN, Bethesda, MD 20892 USA
关键词
D O I
10.1074/jbc.M209486200
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The N-methyl-D-aspartate (NMDA) receptor has four membrane-associated domains, three of which are membrane-spanning (M1, M3, and M4) and one of which is a re-entrant pore loop (M2). The M2-M3 domains have been demonstrated to influence the function of the ion channel, but a similar role for the M4 domain has not been reported. We have identified a methionine residue (Met(823)) in the M4 domain of the NR2A subunit that regulates desensitization and ion channel gating. A tryptophan substitution at this site did not alter the EC50 for glycine or the peak NMDA EC50 but decreased the steady-state NMDA EC50 and markedly increased apparent desensitization, mean open time, and peak current density. Results of rapid solution exchange experiments revealed that changes in microscopic desensitization rates and closing rates could account for the changes in macroscopic desensitization, steady-state NMDA EC50, and current density. Other amino acid substitutions at this site could increase or decrease the rate of desensitization and mean open time of the ion channel. Both mean open time and desensitization were dependent primarily upon the hydrophobic character of the amino acid at the position. These results demonstrate an important role for hydrophobic interactions at Met(823) in regulation of NMDA receptor function.
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页码:276 / 283
页数:8
相关论文
共 52 条
[1]  
Anson LC, 1998, J NEUROSCI, V18, P581
[2]   Mechanisms for activation and antagonism of an AMPA-Sensitive glutamate receptor: Crystal structures of the GluR2 ligand binding core [J].
Armstrong, N ;
Gouaux, E .
NEURON, 2000, 28 (01) :165-181
[3]   Structure of a glutamate-receptor ligand-binding core in complex with kainate [J].
Armstrong, N ;
Sun, Y ;
Chen, GQ ;
Gouaux, E .
NATURE, 1998, 395 (6705) :913-917
[4]   NMDAR channel segments forming the extracellular vestibule inferred from the accessibility of substituted cysteines [J].
Beck, C ;
Wollmuth, LP ;
Seeburg, PH ;
Sakmann, B ;
Kuner, T .
NEURON, 1999, 22 (03) :559-570
[5]   NMDA channel gating is influenced by a tryptophan residue in the M2 domain but calcium permeation is not altered [J].
Buck, DP ;
Howitt, SM ;
Clements, JD .
BIOPHYSICAL JOURNAL, 2000, 79 (05) :2454-2462
[6]   Subtype-dependence of NMDA receptor channel open probability [J].
Chen, NS ;
Luo, T ;
Raymond, LA .
JOURNAL OF NEUROSCIENCE, 1999, 19 (16) :6844-6854
[7]   ACTIVATION KINETICS REVEAL THE NUMBER OF GLUTAMATE AND GLYCINE BINDING-SITES ON THE N-METHYL-D-ASPARTATE RECEPTOR [J].
CLEMENTS, JD ;
WESTBROOK, GL .
NEURON, 1991, 7 (04) :605-613
[8]   THE TIME COURSE OF GLUTAMATE IN THE SYNAPTIC CLEFT [J].
CLEMENTS, JD ;
LESTER, RAJ ;
TONG, G ;
JAHR, CE ;
WESTBROOK, GL .
SCIENCE, 1992, 258 (5087) :1498-1501
[9]  
Colquhoun D, 1998, BRIT J PHARMACOL, V125, P924
[10]   SIMULTANEOUS ANALYSIS OF FAMILIES OF SIGMOIDAL CURVES - APPLICATION TO BIOASSAY, RADIOLIGAND ASSAY, AND PHYSIOLOGICAL DOSE-RESPONSE CURVES [J].
DELEAN, A ;
MUNSON, PJ ;
RODBARD, D .
AMERICAN JOURNAL OF PHYSIOLOGY, 1978, 235 (02) :E97-E102