Inhibition of neuronal nitric-oxide synthase by phosphorylation at Threonine1296 in NG108-15 neuronal cells.
We demonstrate that neuronal nitric-oxide synthase (nNOS) is directly inhibited through the phosphorylation of Thr(1296) in NG108-15 neuronal cells. Treatment of NG108-15 cells expressing nNOS with calyculin A, an inhibitor of protein phosphatase 1 and 2A, revealed a dose-dependent inhibition of nNOS enzyme activity with concomitant phosphorylation of Thr(1296) residue. Cells expressing a phosphorylation-deficient mutant in which Thr(1296) was changed to Ala proved resistant to phosphorylation and suppression of NOS activity. Mimicking phosphorylation mutant of nNOS in which Thr(1296) is changed to Asp showed a significant decrease in nNOS enzyme activity, being competitive with NADPH, relative to the wild-type enzyme. These data suggest that phosphorylation of nNOS at Thr(1296) may involve the attenuation of nitric oxide production in neuronal cells through the decrease of NADPH-binding to the enzyme.
Song
Tao
T
Department of Cell Physiology, Kagawa University, Faculty of Medicine, Miki-cho, Kida-gun, Japan.
Hatano
Naoya
N
Kume
Kodai
K
Sugimoto
Katsuyoshi
K
Yamaguchi
Fuminori
F
Tokuda
Masaaki
M
Watanabe
Yasuo
Y
D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology; D008387:Marine Toxins; D009154:Mutation; D009249:NADP / Q000378:metabolism; D009474:Neurons / Q000201:enzymology*; D009569:Nitric Oxide / Q000096:biosynthesis; D052248:Nitric Oxide Synthase Type I / Q000737:chemistry / Q000378:metabolism*; D019319:Okadaic Acid / Q000494:pharmacology; D010080:Oxazoles / Q000494:pharmacology; D010766:Phosphorylation; D051381:Rats; D013912:Threonine / Q000235:genetics / Q000378:metabolism
D004791:Enzyme Inhibitors; D008387:Marine Toxins; D010080:Oxazoles; D019319:Okadaic Acid; D013912:Threonine; D009569:Nitric Oxide; D009249:NADP; C059041:calyculin A; D052248:Nitric Oxide Synthase Type I