【期刊导读】IJMM（中国医大）：NO通过抑制Akt/PKB、CaM-K II通路防止神经元NOSs1412磷酸化

来自中国医科大学第一附属医院麻醉科宋涛教授研究团队的文章

Int J Mol Med. 2012 Jul;30(1):15-20. doi: 10.3892/ijmm.2012.971. Epub 2012 Apr 20.

Nitric oxide prevents phosphorylation of neuronal nitric oxide synthase at Serine1412 by inhibiting the Akt/PKB and CaM-K II signaling pathways.

Song T, Hatano N, Sugimoto K, Horii M, Yamaguchi F, Tokuda M, Miyamoto Y, Kambe T, Watanabe Y.

Source

Department of Anesthesiology, The First Affiliated Hospital, China Medical University, Shenyang 110001, P.R. China.

Abstract

Neuronal nitric oxide synthase (nNOS) is an important regulatory enzyme in the central nervous system catalyzing the production of NO, which regulates multiple biological processes in the central nervous system. However, the mechanisms by which nNOS activity is regulated are not completely understood. In the present study, the effects of protein kinases on the phosphorylation of nNOS in GH3 rat pituitary tumor cells were evaluated. We show that phosphorylation of nNOS at Ser1412 could be induced by the phosphatidylinositol 3-kinase/protein kinase B (Akt/PKB) agonist insulin, the calcium/calmodulin-dependent protein kinase II (CaM-K II) agonist A23187 or the cAMP-dependent protein kinase A (PKA) agonist IBMX, respectively. The phosphorylation levels of nNOS at Ser1412, induced by activation of Akt/PKB or CaM-K II, but not by PKA signaling, were reduced by pre-treatment with the NO donor diethylamine-NONOate. This inhibitory effect could be reversed by addition of a reducing reagent, dithiothreitol. Furthermore, the levels of phosphorylation of nNOS at Ser1412, induced by Akt/PKB or CaM-K II but not by PKA signaling, were enhanced by inhibition of nNOS activity with 7-nitroindazole. These findings suggest that the activation of nNOS can be catalyzed by at least three protein kinases, Akt/PKB, CaM-K II or PKA. NO generated from nNOS feedback prevents the activation of nNOS by inhibiting either Akt/PKB or CaM-K II but not PKA signaling.

PMID:22576624