Identification of the GABAA receptor alpha 3 subunit in the IMR-32 neuroblastoma cell line.
A previous report has described the presence of t-[35S]-butylbicyclophosphorothionate binding sites and GABA-gated Cl- flux in the human neuroblastoma IMR-32 cell line. We now report the further characterisation of this binding site and, even more important, the identification of the GABAA receptor alpha 3 sub-unit expressed in these cells. Cell membranes prepared from IMR-32 cells were screened by immunoblotting for reactivity with various GABAA receptor alpha subunit-specific antibodies. Of these, only anti-Cys alpha 3 454-467 antibodies recognised specifically and in a dose-dependent manner an immunoreactive band. This M(r) 58,000 immunoreactive species and the N-deglycosylated derivatives were both coincident with the respective homologues found in both calf cerebral cortex membranes and purified receptor preparations. This is the first report of the identification of a specific GABAA receptor subunit expressed in a human cell line, and it therefore provides a convenient model for the study of receptor structure and regulation.
Department of Pharmaceutical Chemistry, School of Pharmacy, London, England.
P J
PJ
Noble
S M
SM
Anderson
R J
RJ
De Souza
A J
AJ
Cross
F A
FA
Stephenson
D000818:Animals; D001643:Bridged Bicyclo Compounds / Q000378:metabolism; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002417:Cattle; D002462:Cell Membrane / Q000737:chemistry; D002540:Cerebral Cortex / Q000737:chemistry; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D015151:Immunoblotting; D008970:Molecular Weight; D009447:Neuroblastoma / Q000737:chemistry*; D011724:Pyridazines / Q000378:metabolism; D011963:Receptors, GABA-A / Q000032:analysis* / Q000378:metabolism; D014407:Tumor Cells, Cultured
D001643:Bridged Bicyclo Compounds; D019086:Bridged Bicyclo Compounds, Heterocyclic; D011724:Pyridazines; D011963:Receptors, GABA-A; C037476:tert-butylbicyclophosphorothionate; C049853:gabazine