title: Structural determinants of ion flow through recombinant glutamate receptor channels.
abstract: Functional glutamate receptor (GluRs) were transiently expressed in cultured mammalian cells from cloned complementary DNAs encoding GluR-A, -B, -C, or -D polypeptides. The steady-state current-voltage (I-V) relations of glutamate- and kainate-induced currents through homomeric channels fell into two classes: channels composed of either the GluR-A, -C, and -D subunits showed doubly rectifying I-V curves, and channels composed of the GluR-B subunits displayed simple outward rectification. The presence of GluR-B subunits in heteromeric GluRs determined the I-V behavior of the resulting channels. Site-directed mutagenesis identified a single amino acid difference (glutamine to arginine) in the putative transmembrane segment TM2 responsible for subunit-specific I-V relationships. The properties of heteromeric wild-type and mutant GluRs revealed that the dominance of GluR-B is due to the arginine residue in the TM2 region.
authors.affiliation: Max-Planck-Institut für medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Federal Republic of Germany.
authors.forename: T A
authors.initials: TA
authors.lastname: Verdoorn
authors.forename: N
authors.initials: N
authors.lastname: Burnashev
authors.forename: H
authors.initials: H
authors.lastname: Monyer
authors.forename: P H
authors.initials: PH
authors.lastname: Seeburg
authors.forename: B
authors.initials: B
authors.lastname: Sakmann
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004252:DNA Mutational Analysis; D005971:Glutamates / Q000502:physiology; D006801:Humans; D015640:Ion Channel Gating; D007473:Ion Channels / Q000502:physiology*; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins / Q000502:physiology; D008969:Molecular Sequence Data; D009841:Oligonucleotides / Q000737:chemistry; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D011994:Recombinant Proteins; D013329:Structure-Activity Relationship
chemical_list: D005971:Glutamates; D007473:Ion Channels; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D009841:Oligonucleotides; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D011994:Recombinant Proteins