Evidence against direct involvement of cyclic AMP-dependent protein phosphorylation in the exocytosis of amylase.
Evidence against direct involvement of cyclic AMP-dependent protein phosphorylation in the exocytosis of amylase.
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反对环 AMP 依赖性蛋白磷酸化直接参与淀粉酶胞吐作用的证据。
DOI：
10.1042/bj2560867
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
T. Takuma
中科院分区：
文献类型：
--
作者：
T. Takuma
为了检查环AMP依赖性蛋白激酶的激活是否与大鼠腮腺细胞淀粉酶的胞吐作用相关，研究了蛋白激酶抑制剂对淀粉酶释放和蛋白质磷酸化的影响。环 AMP 依赖性蛋白激酶的膜渗透性抑制剂 N-[2-(甲基氨基)乙基]-5-异喹啉磺酰胺 (H-8) 和热稳定蛋白激酶抑制剂的肽片段 [PKI-(5-24)-肽和 PKI-(14-24)-酰胺] 强烈抑制细胞匀浆中的环 AMP 依赖性蛋白激酶活性。然而，H-8 对异丙肾上腺素或环 AMP 刺激的完整腮腺细胞或皂苷通透腮腺细胞的淀粉酶释放没有抑制作用。此外，PKI-(5-24)-肽和PKI-(14-24)-酰胺不会抑制皂苷透化细胞中环AMP诱发的淀粉酶释放，而完整或透化细胞中21和26 kDa蛋白质的环AMP依赖性磷酸化被这些抑制剂显着抑制。这些结果表明环AMP依赖性蛋白磷酸化并不直接参与环AMP调节的淀粉酶的胞吐作用。
To examine whether or not the activation of cyclic AMP-dependent protein kinase is coupled to the exocytosis of amylase from rat parotid cells, the effect of protein kinase inhibitors on amylase release and protein phosphorylation was studied. A membrane-permeable inhibitor of cyclic AMP-dependent protein kinase, N-[2-(methylamino)ethyl]-5-isoquinolinesulphonamide (H-8), and peptide fragments of the heat-stable protein kinase inhibitor [PKI-(5-24)-peptide and PKI-(14-24)-amide] strongly inhibited cyclic AMP-dependent protein kinase activity in the cell homogenate. However, H-8 had no inhibitory effect on amylase release from either intact or saponin-permeabilized parotid cells stimulated by isoproterenol or cyclic AMP. Moreover, PKI-(5-24)-peptide and PKI-(14-24)-amide did not inhibit cyclic AMP-evoked amylase release from saponin-permeabilized cells, whereas cyclic AMP-dependent phosphorylations of 21 and 26 kDa proteins in intact or permeabilized cells were markedly inhibited by these inhibitors. These results suggest that cyclic AMP-dependent protein phosphorylation is not directly involved in the exocytosis of amylase regulated by cyclic AMP.