Yoshida A, Takahashi M, Imagawa T, Shigekawa M, Takisawa H, Nakamura T
Department of Biology, Faculty of Science, Osaka University.
J Biochem. 1992 Feb;111(2):186-90. doi: 10.1093/oxfordjournals.jbchem.a123735.
We studied beta-adrenergic agonist-stimulated phosphorylation of the ryanodine receptor in rat cardiac myocytes. The ryanodine receptor solubilized from myocytes and immunoprecipitated by a monoclonal antibody against canine cardiac ryanodine receptor was phosphorylated by the catalytic subunit of cAMP-dependent protein kinase (PKA). Incubation of saponin-permeabilized myocytes with [gamma-32P]ATP also induced ryanodine receptor phosphorylation, which was enhanced significantly in the presence of isoproterenol. This stimulating action of isoproterenol was suppressed by the beta-adrenergic antagonist, propranolol. On the other hand, exogenously added cAMP caused a much larger stimulation of phosphorylation of the ryanodine receptor in permeabilized myocytes. The beta-agonist-induced phosphorylation of the ryanodine receptor was also observed in intact myocytes from the newborn rat heart. These results suggest that the ryanodine receptor is phosphorylated by PKA during beta-adrenergic stimulation of cardiac myocytes.
我们研究了β-肾上腺素能激动剂刺激大鼠心肌细胞中兰尼碱受体的磷酸化情况。从心肌细胞中溶解并用抗犬心肌兰尼碱受体的单克隆抗体免疫沉淀的兰尼碱受体，可被环磷酸腺苷（cAMP）依赖性蛋白激酶（PKA）的催化亚基磷酸化。用[γ-32P]ATP孵育皂素通透的心肌细胞也可诱导兰尼碱受体磷酸化，在异丙肾上腺素存在下这种磷酸化显著增强。异丙肾上腺素的这种刺激作用可被β-肾上腺素能拮抗剂普萘洛尔抑制。另一方面，外源性添加的cAMP对通透心肌细胞中兰尼碱受体磷酸化的刺激作用要大得多。在新生大鼠心脏的完整心肌细胞中也观察到了β-激动剂诱导的兰尼碱受体磷酸化。这些结果表明，在心肌细胞的β-肾上腺素能刺激过程中，兰尼碱受体被PKA磷酸化。
