Functional inhibition of protein kinase C-mediated effects in myocardial tissue is due to the phosphatase 2A.
Functional inhibition of protein kinase C-mediated effects in myocardial tissue is due to the phosphatase 2A.
复制标题
心肌组织中蛋白激酶 C 介导的作用的功能性抑制归因于磷酸酶 2A。
DOI：
10.1042/bj2860851
复制
发表时间：
1992
期刊：
影响因子：
--
通讯作者：
U. Lang
中科院分区：
文献类型：
--
作者：
S. Braconi;D. Church;M. Vallotton;U. Lang
An endogenous protein which inhibits protein kinase C (PKC)-mediated effects has been detected in rat heart ventricular tissue. This functional PKC-inhibitory activity was completely abolished by okadaic acid, making it possible to measure PKC activity in non-purified cell fractions. This suggests that the PKC-inhibitory activity is a type 1 or 2A serine/threonine phosphatase. Confirming this, membrane and cytosolic PKC-inhibitory preparations were found to contain phosphatase activity which was suppressed by okadaic acid, exhibiting an IC50 (concn. required for 50% inhibition) of 1.5-2 nM. Furthermore, okadaic acid stimulated prostacyclin production in rat cardiomyocytes and aortic smooth-muscle cells and, like the PKC activator phorbol 12-myristate 13-acetate, it augmented the prostacyclin formation induced by the Ca2+ ionophore A23187. Our results strongly suggest that the endogenous PKC 'inhibitor' is the cellular phosphatase 2A, which plays an important role in regulating the phosphorylation level of PKC target proteins.
