Structural determinants of ion flow through recombinant glutamate receptor channels.
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.
Verdoorn
T A
TA
Max-Planck-Institut für medizinische Forschung, Abteilung Zellphysiologie, Heidelberg, Federal Republic of Germany.
Burnashev
N
N
Monyer
H
H
Seeburg
P H
PH
Sakmann
B
B
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
D005971:Glutamates; D007473:Ion Channels; D046911:Macromolecular Substances; D008562:Membrane Glycoproteins; D009841:Oligonucleotides; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D011994:Recombinant Proteins