Stoichiometry of a recombinant GABAA receptor deduced from mutation-induced rectification.
Ligand-gated ion channels generally display a heterooligomeric subunit structure. The present report describes an electrophysiological method that provides criteria indicating the subunit stoichiometry of a recombinant GABAA receptor composed of alpha 3, beta 2 and gamma 2 subunits. Our results exclude the stoichiometries 3 alpha 1 beta 1 gamma, 1 alpha 3 beta 1 gamma, 1 alpha 1 beta 3 gamma and suggest that the possible subunit stoichiometries for this receptor are 2 alpha 1 beta 2 gamma, 2 alpha 2 beta 1 gamma or 1 alpha 2 beta 2 gamma, of which the alpha subunit composition 2 alpha 1 beta 2 gamma may be favoured. The method is based on the quantification of the outward rectification of the GABA-evoked current induced by point mutation of charged amino acids located near the ion channel pore.
Backus
K H
KH
Institute of Pharmacology, University of Zürich, Switzerland.
Arigoni
M
M
Drescher
U
U
Scheurer
L
L
Malherbe
P
P
Möhler
H
H
Benson
J A
JA
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D004594:Electrophysiology; D006801:Humans; D007473:Ion Channels / Q000378:metabolism; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D051381:Rats; D011963:Receptors, GABA-A / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics
D007473:Ion Channels; D011963:Receptors, GABA-A; D011994:Recombinant Proteins