The interaction of a kainate receptor from goldfish brain with a pertussis toxin-sensitive GTP-binding protein.
Kainate receptors are present in high concentrations in goldfish brain (Henley and Oswald, 1988a and b; Ziegra et al., 1990), possibly in neuronal and glial cells. In a number of systems, the kainate receptor has been assumed to be an integral ion channel (Watkins and Evans, 1981); but, for some kainate receptors, ion channel activity has not been demonstrated (Wada et al., 1989). This study presents evidence that a portion of the [3H]kainate-binding sites in goldfish brain is sensitive to guanine nucleotides, with a loss of high affinity binding in the presence of nonhydrolyzable GTP analogs. Pertussis toxin pretreatment of membranes causes a loss of high affinity [3H]kainate binding and of the guanine nucleotide-sensitive binding. Pertussis toxin catalyzes the specific [32P]ADP-ribosylation of a 40-kDa substrate in a kainate-sensitive manner. In addition, incorporation of [alpha-32P]GTP-gamma-azidoanilide by photoaffinity labeling was enhanced in the presence of kainate. These results indicate that a subpopulation of [3H]kainate-binding sites in goldfish brain may be coupled to G proteins.
Department of Pharmacology, New York State College of Veterinary Medicine, Cornell University, Ithaca 14853.
J M
JM
Willard
C J
CJ
Ziegra
R E
RE
Oswald
D000246:Adenosine Diphosphate Ribose / Q000378:metabolism; D000345:Affinity Labels; D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001923:Brain Chemistry; D019204:GTP-Binding Proteins / Q000378:metabolism*; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D006054:Goldfish; D007608:Kainic Acid / Q000378:metabolism*; D037342:Pertussis Toxin; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D013574:Synaptosomes / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000246:Adenosine Diphosphate Ribose; D000345:Affinity Labels; D019204:GTP-Binding Proteins; D005971:Glutamates; D018698:Glutamic Acid; D007608:Kainic Acid; D037342:Pertussis Toxin; D018092:Kainic Acid Receptors; D017981:Receptors, Neurotransmitter; D010566:Virulence Factors, Bordetella