RECEPTOR AND TRANSPORTER REGULATION OF NO SYNTHASES

内皮型和诱导型一氧化氮合酶(eNOS和iNOS)在正常的血管生理和血管病理中都起着关键的调节作用。初步研究表明，eNOS与血管内皮细胞中的缓激肽B2受体和CAT1阳离子氨基酸转运体直接相互作用。此外，已有研究表明，iNOS与CAT2阳离子氨基酸转运体共同诱导血管平滑肌细胞表达iNOS。由于iNOS和CAT2在结构和功能上与eNOS和CAT1非常相似，我们推测iNOS和CAT2也在平滑肌中相互作用。在这一应用中，我们建议检验eNOS在内皮细胞中通过与B2受体的抑制相互作用来调节的假设。我们还将确定酪氨酸磷酸化在相互作用调节中的作用，并将定义两种蛋白质中负责相互作用的结构域。我们进一步建议检验eNOS-CAT1相互作用促进内皮细胞释放NO的假设，并将确定这两种蛋白质中相互作用的结构域是什么。最后，我们将检验这一假设，即iNOS-CAT2相互作用促进血管平滑肌细胞释放NO，并将定义参与相互作用的两种蛋白质中的结构域。

The endothelial and inducible nitric oxide synthases (eNOS and iNOS) have key regulatory roles in both normal vascular physiology and in vascular pathology. Preliminary studies presented in this proposal indicate that eNOS interacts directly with the bradykinin B2 receptor and with the CAT1 cationic amino acid transporter in vascular endothelial cells. In addition, it has been shown that iNOS is coinduced with the CAT2 cationic amino acid transporter in vascular smooth muscle cells. Because iNOS and CAT2 are structurally and functionally very similar to eNOS and CAT1, we postulate that iNOS and CAT2 also interact in smooth muscle. In this application, we propose to test the hypothesis that eNOS is regulated in endothelial cells by inhibitory interactions with the B2 receptor. We will also determine the role of tyrosine phosphorylation in regulation of the interaction and will define the domains in the two proteins that are responsible for the interaction. We further propose to test the hypothesis that the eNOS-CAT1 interaction facilitates NO release from endothelial cells and will determine what the interacting domains are in the two proteins. Finally, we will test the hypothesis that the iNOS-CAT2 interaction facilitates NO release from vascular smooth muscle cells and will define the domains in the two proteins that are involved in the interaction.