CDK5 phosphorylates eNOS at Ser-113 and regulates NO production.
Phosphorylation of endothelial nitric oxide synthase (eNOS) is key mechanism in response to various forms of cellular stimulation. Through protein nitration by peroxynitrite, eNOS is believed to be responsible for the major abnormalities in several important neurodegenerative diseases including Alzheimer's (AD) and Parkinson's diseases (PD). Recent studies provide important in vivo evidence that hyperactivation of Cdk5 by p25 plays an essential role in the cell death of neurons in experimental models of AD and PD. This study focuses on the functional regulation of eNOS by Cdk5/p35 complex in a phosphorylation dependent manner. Our results showed that Cdk5 can phosphorylate eNOS both in vitro and in vivo. In vitro kinase assay together with the bioinformatic analysis and site direct mutagenesis revealed that Ser-113 is the major phosphorylation site for Cdk5. Most interestingly, the nitrite production was significantly reduced in eNOS and Cdk5/p35 co-transfected SH-SY5Y cells when compared with co-transfection of Cdk5/p35 and S113A. Together, our data suggest that Cdk5 can phosphorylate eNOS at the Ser-113 site and down-regulate eNOS-derived NO levels.
Lee
Chien-Hsing
CH
Institute of Clinical Medicine, National Cheng Kung University, Tainan, Taiwan.
Wei
Yin-Win
YW
Huang
Yi-Ting
YT
Lin
Yuh-Te
YT
Lee
Yu-Cheng
YC
Lee
Kuen-Haur
KH
Lu
Pei-Jung
PJ
D000818:Animals; D045744:Cell Line, Tumor; D051360:Cyclin-Dependent Kinase 5 / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000096:biosynthesis*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010766:Phosphorylation; D010768:Phosphoserine / Q000378:metabolism*; D011485:Protein Binding; D051381:Rats
D010768:Phosphoserine; D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D051360:Cyclin-Dependent Kinase 5; C495905:CDK5 protein, human; C495907:Cdk5 protein, rat