Effects of GTP analogues and activation of endogenous protein kinases on photoaffinity labeling with [3H](+)PN200-110 of crude membranes from rat heart and brain.
The effects of GTP analogues and conditions in which various endogenous protein kinases were activated on photoaffinity labeling with [3H](+)PN200-110 (PN) of crude membranes from rat cardiac muscle and whole brain were investigated. Photoaffinity labeling with 20 nM [3H](+)PN of these crude membranes was decreased by 100 microM GTP-gamma-S, but not by 100 microM GTP or 100 microM GDP-beta-S. Similar results were obtained on the effects of GTP and its analogues on the specific binding of 20 nM [3H](+)PN to these crude membranes under the same conditions. Activation of endogenous protein kinases in these crude membranes did not influence the photoaffinity labeling with [3H](+)PN. These results suggested the binding sites, or DPH-sensitive, or L-type, calcium channels in curde membranes from rat cardiac muscle and whole brain are directly or indirectly modulated by endogenous GTP-binding protein, but not by various endogenous protein kinases in these crude membranes.
Ichida
S
S
Department of Biological Chemistry, Faculty of Pharmacy, Kinki University, Higashi-Osaka, Japan.
Masada
A
A
Yoshioka
T
T
Kishino
H
H
Akimoto
T
T
Wada
T
T
D000345:Affinity Labels; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004095:Dihydropyridines; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives*; D017275:Isradipine; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010777:Photochemistry; D011494:Protein Kinases / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D014316:Tritium
D000345:Affinity Labels; D002121:Calcium Channel Blockers; D004095:Dihydropyridines; D014316:Tritium; D006160:Guanosine Triphosphate; D011494:Protein Kinases; D017275:Isradipine