Variant estrogen receptor-c-Src molecular interdependence and c-Src structural requirements for endothelial NO synthase activation

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 104; no. 42; pp. 16468 - 16473
• Main Authors: Li, Lei, Hisamoto, Koji, Kim, Kyung Hee, Haynes, M. Page, Bauer, Philip M, Sanjay, Archana, Collinge, Mark, Baron, Roland, Sessa, William C, Bender, Jeffrey R
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 16.10.2007; National Acad Sciences
• Subjects: Animals; Antibodies; Aorta - drug effects; Aorta - enzymology; Biological Sciences; Cell Membrane - chemistry; Cell Membrane - metabolism; Cell membranes; Cells; Coronary vessels; COS cells; Enzyme Activation; Estradiol - pharmacology; Estrogen Receptor alpha - analysis; Estrogen Receptor alpha - genetics; Estrogen Receptor alpha - metabolism; Estrogens; Humans; Kinases; Mice; Molecular interactions; Nitric Oxide Synthase Type III - metabolism; P branes; Phosphorylation; Protein Structure, Tertiary; Protein-Tyrosine Kinases - analysis; Protein-Tyrosine Kinases - chemistry; Protein-Tyrosine Kinases - metabolism; RNA Splicing; Rodents; Signal transduction; src-Family Kinases; Vasodilation; Vehicles
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0704315104

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 17β-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 α 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.