title: Functional expression of a recombinant unitary glutamate receptor from Xenopus, which contains N-methyl-D-aspartate (NMDA) and non-NMDA receptor subunits.
abstract: A cDNA encoding a 100-kDa subunit (XenNR1) of the N-methyl-D-aspartate (NMDA) glutamate receptor type has been cloned from Xenopus central nervous system. When XenNR1 is coexpressed in a mammalian cell line with a recently cloned 51-kDa non-NMDA receptor subunit (XenU1), also from Xenopus, it forms a functional unitary receptor exhibiting the pharmacological properties characteristic of both NMDA and non-NMDA receptors. Firstly, XenU1 can replace NR2 subunits, in complementing XenNR1 to introduce the ligand binding properties of a complete NMDA receptor. Second, responses to both NMDA and non-NMDA receptor agonists and antagonists were obtained in patch-clamp recordings from the cotransfected cells, but no significant responses were recorded when the cells were singly transfected. Third, from solubilized cell membranes from the cotransfected cells, an antibody to the NR1 subunit coprecipitated the binding sites of the non-NMDA receptor subunit. The unitary glutamate receptor has a unique set of properties that denote intersubunit interaction, including a glycine requirement for the responses to non-NMDA as well as to NMDA receptor agonists and voltage-dependent block by Mg2+ of the non-NMDA agonist responses.
authors.affiliation: Molecular Neurobiology Unit, Royal Free Hospital School of Medicine, London NW3 2PF, United Kingdom. barnard@rfhsm.ac.uk
authors.forename: M M
authors.initials: MM
authors.lastname: Soloviev
authors.forename: M J
authors.initials: MJ
authors.lastname: Brierley
authors.forename: Z Y
authors.initials: ZY
authors.lastname: Shao
authors.forename: I R
authors.initials: IR
authors.lastname: Mellor
authors.forename: T M
authors.initials: TM
authors.lastname: Volkova
authors.forename: R
authors.initials: R
authors.lastname: Kamboj
authors.forename: H
authors.initials: H
authors.lastname: Ishimaru
authors.forename: H
authors.initials: H
authors.lastname: Sudan
authors.forename: J
authors.initials: J
authors.lastname: Harris
authors.forename: R L
authors.initials: RL
authors.lastname: Foldes
authors.forename: E V
authors.initials: EV
authors.lastname: Grishin
authors.forename: P N
authors.initials: PN
authors.lastname: Usherwood
authors.forename: E A
authors.initials: EA
authors.lastname: Barnard
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D004553:Electric Conductivity; D005816:Genetic Complementation Test; D005998:Glycine / Q000502:physiology; D015640:Ion Channel Gating; D008024:Ligands; D046911:Macromolecular Substances; D051379:Mice; D008969:Molecular Sequence Data; D016202:N-Methylaspartate / Q000378:metabolism; D011233:Precipitin Tests; D051381:Rats; D017470:Receptors, Glutamate / Q000737:chemistry* / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000737:chemistry* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry; D016415:Sequence Alignment; D013329:Structure-Activity Relationship; D014982:Xenopus laevis
chemical_list: D008024:Ligands; D046911:Macromolecular Substances; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; D011994:Recombinant Proteins; D016202:N-Methylaspartate; D005998:Glycine