GTP-binding protein couples with metabotropic glutamate receptor in bovine retinal on-bipolar cell.
GTP-binding protein (G protein) linking to metabotropic glutamate receptor of bovine retinal on-bipolar cell was studied by use of pharmacologically selective ligands, 2-amino-4-phosphonobutyric acid (APB) on bacterial toxin-catalyzed ADP-ribosylation and GTP gamma S-binding. In contrast to the electrophysiological findings reported, G protein coupling to APB-sensitive glutamate receptor served as a substrate for pertussis toxin but did not for cholera toxin. Several glutamate analogues effective on on-bipolar cell, as well as APB, increased GTP gamma S binding to retinal membranes devoid of rod outer segments. The enhancement of GTP gamma S binding by APB was completely abolished when the membranes were pretreated with pertussis toxin and NAD. These results suggest that, in retinal on-bipolar cell, the G protein which couples metabotropic glutamate receptor to hyperpolarizing response of the cell is sensitive to pertussis toxin.
Kikkawa
S
S
Department of Life Science, Himeji Institute of Technology, Hyogo, Japan.
Nakagawa
M
M
Iwasa
T
T
Kaneko
A
A
Tsuda
M
M
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D002772:Cholera Toxin / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005971:Glutamates; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D007700:Kinetics; D009243:NAD / Q000378:metabolism*; D037342:Pertussis Toxin; D017470:Receptors, Glutamate / Q000302:isolation & purification / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000378:metabolism*; D012374:Rod Cell Outer Segment; D010566:Virulence Factors, Bordetella / Q000378:metabolism
D005971:Glutamates; D017470:Receptors, Glutamate; D010566:Virulence Factors, Bordetella; D009243:NAD; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins