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. |
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Authors: | S Ichida A Masada T Yoshioka H Kishino T Akimoto T Wada |
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Institution: | Department of Biological Chemistry, Faculty of Pharmacy, Kinki University, Higashi-Osaka, Japan. |
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Abstract: | 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. |
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