Guanine nucleotide regulation of VIP binding to rat peritoneal macrophage membranes.
In the present study, we have examined the effect of guanine nucleotides on VIP binding to rat peritoneal macrophage membranes. Both guanosine 5'-triphosphate (GTP) and its nonhydrolizable analog guanosine 5'-beta, Y-imidotriphosphate [Gpp(NH)p] inhibited, in a dose-dependent manner, the VIP binding to its specific binding sites. Half-maximal inhibition (IC50) was observed at 5.4 +/- 0.5 microM GTP. The inhibitory effect of GTP was due to an increase of the dissociation rate of peptide bound to membranes. The specificity of the binding inhibition was assessed from the lack of action of the other nucleotides tested. These results directly suggest the coupling of VIP binding sites with guanine nucleotide binding proteins in rat peritoneal macrophage membranes.
Segura
J J
JJ
Department of Medical Biochemistry and Molecular Biology, School of Medicine, University of Sevilla, Spain.
Guerrero
J M
JM
Goberna
R
R
Calvo
J R
JR
D000818:Animals; D001665:Binding Sites; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D019204:GTP-Binding Proteins / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000494:pharmacology*; D006165:Guanylyl Imidodiphosphate / Q000494:pharmacology; D066298:In Vitro Techniques; D007700:Kinetics; D008264:Macrophages / Q000187:drug effects* / Q000378:metabolism; D010529:Peritoneal Cavity / Q000166:cytology; D051381:Rats; D017208:Rats, Wistar; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism*
D006165:Guanylyl Imidodiphosphate; D014660:Vasoactive Intestinal Peptide; D006160:Guanosine Triphosphate; D019204:GTP-Binding Proteins