Interplay of myosin phosphatase and protein phosphatase-2A in the regulation of endothelial nitric-oxide synthase phosphorylation and nitric oxide production.
Interplay of myosin phosphatase and protein phosphatase-2A in the regulation of endothelial nitric-oxide synthase phosphorylation and nitric oxide production.
复制标题
DOI：
10.1038/srep44698
复制
发表时间：
2017-03-16
影响因子：
4.6
通讯作者：
Erdődi F
中科院分区：
文献类型：
--
作者：
Bátori R;Bécsi B;Nagy D;Kónya Z;Hegedűs C;Bordán Z;Verin A;Lontay B;Erdődi F
蛋白激酶C或RhoA激活的激酶抑制内皮型一氧化氮合酶（eNOS）Thr 497（eNOSpThr 497）的磷酸化是eNOS活性的主要调节决定因素。参与eNOSpThr 497去磷酸化的信号传导机制尚未阐明。本研究鉴定了由蛋白磷酸酶-1催化亚基（PP 1c）和肌球蛋白磷酸酶靶亚基-1（MYPT 1）组成的肌球蛋白磷酸酶（MP）全酶为eNOSpThr 497磷酸酶。支持这一发现的是：（i）eNOS和MYPT 1在各种内皮细胞（EC）和体外结合试验中相互作用（ii）MYPT 1靶向并刺激PP 1c朝向eNOSpThr 497底物（iii）MYPT 1在Thr 696处的磷酸化（MYPT 1 pThr 696）控制MP对eNOSpThr 497的活性。磷酸酶抑制剂抑制内皮细胞的NO产生和跨内皮阻力（TER）。相反，表没食子儿茶素-3-没食子酸酯（EGCG）通过67 kDa层粘连蛋白受体（67 LR）向EC发出信号，导致蛋白磷酸酶-2A（PP 2A）的蛋白激酶A依赖性活化。PP 2A使MYPT 1 pThr 696去磷酸化，从而刺激MP活性，诱导eNOSpThr 497和20 kDa肌球蛋白II轻链的去磷酸化。因此，MP和PP 2A的相互作用涉及EC功能的生理调节，这意味着这些磷酸酶的EGCG依赖性活化导致NO产生增强和EC屏障改善。
The inhibitory phosphorylation of endothelial nitric oxide (NO) synthase (eNOS) at Thr497 (eNOSpThr497) by protein kinase C or RhoA-activated kinase is a major regulatory determinant of eNOS activity. The signalling mechanisms involved in the dephosphorylation of eNOSpThr497 have not yet been clarified. This study identifies myosin phosphatase (MP) holoenzyme consisting of protein phosphatase-1 catalytic subunit (PP1c) and MP target subunit-1 (MYPT1) as an eNOSpThr497 phosphatase. In support of this finding are: (i) eNOS and MYPT1 interacts in various endothelial cells (ECs) and in in vitro binding assays (ii) MYPT1 targets and stimulates PP1c toward eNOSpThr497 substrate (iii) phosphorylation of MYPT1 at Thr696 (MYPT1pThr696) controls the activity of MP on eNOSpThr497. Phosphatase inhibition suppresses both NO production and transendothelial resistance (TER) of ECs. In contrast, epigallocatechin-3-gallate (EGCG) signals ECs via the 67 kDa laminin-receptor (67LR) resulting in protein kinase A dependent activation of protein phosphatase-2A (PP2A). PP2A dephosphorylates MYPT1pThr696 and thereby stimulates MP activity inducing dephosphorylation of eNOSpThr497 and the 20 kDa myosin II light chains. Thus an interplay of MP and PP2A is involved in the physiological regulation of EC functions implying that an EGCG dependent activation of these phosphatases leads to enhanced NO production and EC barrier improvement.