Agonist-stimulated endothelial nitric oxide synthase activation and vascular relaxation. Role of eNOS phosphorylation at Tyr83.
Tyr83 in endothelial nitric oxide synthase (eNOS) has been identified previously as a site of Src kinase-mediated phosphorylation of eNOS in bovine aortic endothelial cells (BAECs) that is phosphorylated in response to oxidant stress. In the present study, we have used a phospho-specific antibody to show that Tyr83 in eNOS is also phosphorylated in both BAECs and intact blood vessel segments in response to treatment with a variety of different eNOS-activating agonists, including thapsigargin, vascular endothelial growth factor, bradykinin, ATP, sphingosine-1-phosphate, estrogen, angiopoietin, and acetylcholine. Agonist stimulation of eNOS Tyr83 phosphorylation as well as agonist stimulation of endothelial NO release in BAECs is blocked by Src kinase inhibition by either 4-amino-5-(4-chlorophenyl)-7-(t-butyl) pyrazolo [3,4-d] pyrimidine (PP2) or by dominant negative Src. Mutation of Tyr83 to a nonphosphorylatable Phe blocks agonist stimulation of NO release from eNOS-reconstituted eNOS knockdown endothelial cells. Mutation of Tyr83 also attenuates agonist-induced relaxation of eNOS-reconstituted aortic rings from eNOS knockout mice. Phosphorylation of eNOS at Tyr83 thus appears to be a common covalent modification that is induced, not only by oxidant stress but also by other physiologically relevant extracellular signals known to be important in regulation of eNOS activity in vivo. Moreover, our results demonstrate an important role for Src-mediated phosphorylation of eNOS at Tyr83 in agonist stimulation of eNOS activation and vascular relaxation.
Fulton
David
D
Vascular Biology Center, Medical College of Georgia, 1459 Laney Walker Blvd, Augusta, GA 30912-2500, USA.
Ruan
Ling
L
Sood
Sarika G
SG
Li
Chunying
C
Zhang
Qian
Q
Venema
Richard C
RC
D000255:Adenosine Triphosphate / Q000494:pharmacology; D042682:Angiopoietins / Q000494:pharmacology; D000818:Animals; D001011:Aorta / Q000166:cytology; D001920:Bradykinin / Q000494:pharmacology; D019556:COS Cells; D002417:Cattle; D002522:Chlorocebus aethiops; D042783:Endothelial Cells / Q000166:cytology / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D006801:Humans; D007668:Kidney / Q000166:cytology; D008246:Lysophospholipids / Q000494:pharmacology; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000235:genetics / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D010766:Phosphorylation / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D014443:Tyrosine / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology*; D014664:Vasodilation / Q000502:physiology*; D019061:src-Family Kinases / Q000378:metabolism
D042682:Angiopoietins; D004791:Enzyme Inhibitors; D004967:Estrogens; D008246:Lysophospholipids; D042461:Vascular Endothelial Growth Factor A; C060506:sphingosine 1-phosphate; D009569:Nitric Oxide; D014443:Tyrosine; D019284:Thapsigargin; D000255:Adenosine Triphosphate; D052247:Nitric Oxide Synthase Type II; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D019061:src-Family Kinases; D013110:Sphingosine; D001920:Bradykinin