title: Variant estrogen receptor-c-Src molecular interdependence and c-Src structural requirements for endothelial NO synthase activation.
abstract: Little is known about the tyrosine kinase c-Src's function in the systemic circulation, in particular its role in arterial responses to hormonal stimuli. In human aortic and venous endothelial cells, c-Src is indispensable for 17beta-estradiol (E2)-stimulated phosphatidylinositol 3-kinase/Akt/endothelial NO synthase (eNOS) pathway activation, a possible mechanism in E2-mediated vascular protection. Here we show that c-Src supports basal and E2-stimulated NO production and is required for E2-induced vasorelaxation in murine aortas. Only membrane c-Src is structurally and functionally involved in E2-induced eNOS activation. Independent of c-Src kinase activity, c-Src is associated with an N-terminally truncated estrogen receptor alpha variant (ER46) and eNOS in the plasma membrane through its "open" (substrate-accessible) conformation. In the presence of E2, c-Src kinase is activated by membrane ER46 and in turn phosphorylates ER46 for subsequent ER46 and c-Src membrane recruitment, the assembly of an eNOS-centered membrane macrocomplex, and membrane-initiated eNOS activation. Overall, these results provide insights into a critical role for the tyrosine kinase c-Src in estrogen-stimulated arterial responses, and in membrane-initiated rapid signal transduction, for which obligate complex assembly and localization require the c-Src substrate-accessible structure.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Yale University School of Medicine, 300 Cedar Street, New Haven, CT 06520, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Li
authors.forename: Koji
authors.initials: K
authors.lastname: Hisamoto
authors.forename: Kyung Hee
authors.initials: KH
authors.lastname: Kim
authors.forename: M Page
authors.initials: MP
authors.lastname: Haynes
authors.forename: Philip M
authors.initials: PM
authors.lastname: Bauer
authors.forename: Archana
authors.initials: A
authors.lastname: Sanjay
authors.forename: Mark
authors.initials: M
authors.lastname: Collinge
authors.forename: Roland
authors.initials: R
authors.lastname: Baron
authors.forename: William C
authors.initials: WC
authors.lastname: Sessa
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Bender
mesh_terms: D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000201:enzymology*; D000081247:CSK Tyrosine-Protein Kinase; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D004789:Enzyme Activation; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D051379:Mice; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D011505:Protein-Tyrosine Kinases / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D012326:RNA Splicing; D014664:Vasodilation; D019061:src-Family Kinases
chemical_list: D047628:Estrogen Receptor alpha; D004958:Estradiol; D052250:Nitric Oxide Synthase Type III; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; C000631346:CSK protein, human