TY - JOUR
T1 - Activation of endothelial nitric oxide synthase is dependent on its interaction with globular actin in human umbilical vein endothelial cells
AU - Mi, Qiongyu
AU - Chen, Nan
AU - Shaifta, Yasin
AU - Xie, Liping
AU - Lu, Hui
AU - Liu, Zhen
AU - Chen, Qi
AU - Hamid, Colleen
AU - Becker, Silke
AU - Ji, Yong
AU - Ferro, Albert
PY - 2011/9
Y1 - 2011/9
N2 - Endothelial nitric oxide synthase (eNOS) has been reported to associate with globular actin, and this association increases eNOS activity. Adenosine, histamine, salbutamol and thrombin cause activation of eNOS through widely different mechanisms. Whether these eNOS agonists can regulate eNOS activity through affecting its association with actin is unknown. As previously reported, we confirmed in cultured human umbilical vein endothelial cells (HUVEC) that histamine and thrombin increased intracellular Ca2+ whereas adenosine and salbutamol did not, and that these four agonists caused different effects on actin filament structure. Nevertheless, despite their divergent effects on intracellular Ca2+ and on actin filament structure, we found by immunoprecipitation that adenosine, histamine, salbutamol and thrombin all caused an increase in association between eNOS and globular actin. This increase of association was inhibited by pre-treatment with phalloidin, an actin filament stabilizer. All of these agonists also increased phosphorylation of eNOS on serine residue 1177, eNOS activity, and cyclic guanosine-3', 5'-monophosphate, and these increases were all attenuated by phalloidin. Agonist-induced phosphorylation of eNOS on serine 1177 was attenuated by Akt inhibition, whereas association of eNOS with actin was not. We also found, in HEK-293 cells transfected with the eNOS mutants eNOS-S1177A or eNOS-S1177D, that the association between eNOS and globular actin was decreased as compared to cells transfected with wild-type eNOS. We conclude that association of globular actin with eNOS plays an essential and necessary role in agonist-induced eNOS activation, through enabling its phosphorylation by Akt at serine residue 1177. (C) 2011 Elsevier Ltd. All rights reserved.
AB - Endothelial nitric oxide synthase (eNOS) has been reported to associate with globular actin, and this association increases eNOS activity. Adenosine, histamine, salbutamol and thrombin cause activation of eNOS through widely different mechanisms. Whether these eNOS agonists can regulate eNOS activity through affecting its association with actin is unknown. As previously reported, we confirmed in cultured human umbilical vein endothelial cells (HUVEC) that histamine and thrombin increased intracellular Ca2+ whereas adenosine and salbutamol did not, and that these four agonists caused different effects on actin filament structure. Nevertheless, despite their divergent effects on intracellular Ca2+ and on actin filament structure, we found by immunoprecipitation that adenosine, histamine, salbutamol and thrombin all caused an increase in association between eNOS and globular actin. This increase of association was inhibited by pre-treatment with phalloidin, an actin filament stabilizer. All of these agonists also increased phosphorylation of eNOS on serine residue 1177, eNOS activity, and cyclic guanosine-3', 5'-monophosphate, and these increases were all attenuated by phalloidin. Agonist-induced phosphorylation of eNOS on serine 1177 was attenuated by Akt inhibition, whereas association of eNOS with actin was not. We also found, in HEK-293 cells transfected with the eNOS mutants eNOS-S1177A or eNOS-S1177D, that the association between eNOS and globular actin was decreased as compared to cells transfected with wild-type eNOS. We conclude that association of globular actin with eNOS plays an essential and necessary role in agonist-induced eNOS activation, through enabling its phosphorylation by Akt at serine residue 1177. (C) 2011 Elsevier Ltd. All rights reserved.
U2 - 10.1016/j.yjmcc.2011.06.017
DO - 10.1016/j.yjmcc.2011.06.017
M3 - Article
SN - 1095-8584
VL - 51
SP - 419
EP - 427
JO - Journal of Molecular and Cellular Cardiology
JF - Journal of Molecular and Cellular Cardiology
IS - 3
ER -