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dc.contributor.authorLi, Chunying
dc.date.accessioned2021-02-22T20:24:49Z
dc.date.available2021-02-22T20:24:49Z
dc.date.issued2006-08
dc.identifier.urien
dc.identifier.urihttp://hdl.handle.net/10675.2/623872
dc.descriptionThe file you are attempting to access is currently restricted to Augusta University. Please log in with your NetID if off campus.
dc.description.abstractEndothelial nitric oxide synthase ( eNOS) catalyzes the conversion of L-arginine to Lcitrulline and nitric oxide (NO). Protein phosphorylation and protein-protein interactions are two major mechanisms for eNOS regulation at the post-translational level, three aspects of which have been investigated in this study. The first aspect of eNOS regulation that we have examined is whether endos\atin (ES) is a novel eNOS-activating agonist responsible for stimulating multi-site eNOS phosphorylation in endothelial cells. We show that ES induces acute endothelial NO release accompanied by eNOS phosphorylation events in cultured bovine aortic endothelial cells (BAECs ). ES also induces relaxation of rat aortic rings. The second aspect of eNOS regulation that we have examined is the role of individual eNOS serine and threonine phosphorylation sites in the regulation of eNOS activity in BAECs. We mutated all five Thr- and Ser- sites of eNOS phosphorylation to aspartate or alanine and overexpressed the proteins in BAECs using adenoviral-mediated gene transfer. We show that mimicking phosphorylation of Ser-116 and Thr-497 is inhibitory, and mimicking phosphorylation of Ser-617, Ser-635 and Ser- 1179 is stimulatory. Mimicking phosphorylation of Ser-635 and Ser-1179 together does not show synergistic effects on endothelial NO release. In addition, removal of any of the five Ser/Thr phosphorylation sites does not affect thapsigargin- or VEGF-stimulated NO release. A final aspect of eNOS regulation that we have investigated is the role of proteinprotein interactions of eNOS with the CAT (cationic amino acid transporter)-! arginine transporter. We show that eNOS interacts directly with CAT-1 and that overexpression of CAT-I proteins in BAECs results in significant increases in NO release which is not altered by the CAT-I inhibitor, L-lysine, suggesting that NO production in this in vitro model is independent of CAT-I mediated arginine transport. Furthermore, eNOS enzymatic activity is increased in lysates ofCAT-I-overexpressing cells accompanied by increased eNOS association with CAT-I, alterations of eNOS phosphorylation and eNOS association with caveolin-1. The present study adds to the knowledge of the regulation of eNOS by multi-site phosphorylation and protein-protein interactions.en_US
dc.language.isoen_USen_US
dc.publisherMedical College of Georgiaen_US
dc.rightsCopyright protected. Unauthorized reproduction or use beyond the exceptions granted by the Fair Use clause of U.S. Copyright law may violate federal law.en_US
dc.subjectEndostatinen_US
dc.subjecteNOS phosporylationen_US
dc.subjectProtein-protein interactionen_US
dc.titleEnos Regulation by Phosphorylation and Protein-Protein Interactionsen_US
dc.typeDissertationen_US
dc.contributor.departmentVascular Biology Centeren_US
dc.description.advisorVenema, Richard C
dc.description.majorMajor in Vascular Biologyen_US
dc.description.committeeCatravas, John D
dc.description.committeeCaldwell, R. William
dc.description.committeeBarman, Scott A
dc.description.committeeFulton, David
dc.description.degreeDoctor of Philosophyen_US
dc.embargoen
refterms.dateFOA2021-02-22T20:24:50Z


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