Functional coupling of a human retinal metabotropic glutamate receptor (hmGluR6) to bovine rod transducin and rat Go in an in vitro reconstitution system.
The cDNA encoding hmGluR6, appended with a 15-amino acid antibody epitope (1D4), was transiently transfected in COS-7 cells. The receptor was purified from COS cell membranes using an antibody affinity column. The purified receptor was then reconstituted into lipid vesicles, and its ability to activate either transducin, the rod photoreceptor-specific GTP-binding protein, or the alpha subunit of Go was assayed in vitro using a guanosine 5'-3-O-(thio)triphosphate binding assay. Activation of both transducin and Go was observed. The rate of Go activation was 18-fold greater than the rate of transducin activation. This indicates that the coupling of mGluR6 to Go is more efficient and suggests that Go may be involved in coupling to mGluR6 in ON-bipolar cells.
Weng
K
K
Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, Maryland 21250, USA.
Lu
C
C
Daggett
L P
LP
Kuhn
R
R
Flor
P J
PJ
Johnson
E C
EC
Robinson
P R
PR
D000595:Amino Acid Sequence; D000613:Aminobutyrates / Q000494:pharmacology; D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D019556:COS Cells; D002417:Cattle; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019204:GTP-Binding Proteins / Q000378:metabolism*; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008969:Molecular Sequence Data; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D015293:Transducin / Q000378:metabolism*; D014162:Transfection
D000613:Aminobutyrates; D000927:Anticonvulsants; D018690:Excitatory Amino Acid Agonists; D018094:Receptors, Metabotropic Glutamate; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D015293:Transducin; C012729:2-amino-4-phosphonobutyric acid