HSP90 AND THE ENDOTHELIAL NITRIC OXIDE SYNTHASE

内皮型一氧化氮合酶(ENOS)作为一氧化氮合酶(NO)的合成体，在调节血管紧张性、血小板和白细胞与内皮细胞的黏附、ET-1的产生、血管平滑肌的增殖和血管病变的形成等方面发挥着重要作用。近年来，eNOS已被证明与90 kDa热休克蛋白Hsp90直接结合，但两者之间的相互作用结构域尚未确定。Hsp90与eNOS的相互作用增强已被多种治疗方法证实，并与eNOS活性的增加有关，这种作用可被Hsp90的特异性抑制剂格尔达那霉素所阻断。Hsp90激活eNOS的机制尚不清楚。由于其作为分子伴侣的作用，Hsp90可以稳定和阻止eNOS的部分折叠或二聚体的聚集，从而提高整体活性。此外，Hsp90还可能改变eNOS的三维结构，影响钙调蛋白(CaM)等重要辅助因子的结合。因此，这个项目的目标是双重的，绘制Hsp90和eNOS之间的相互作用结构域，并研究Hsp90上调eNOS活性的潜在机制。

eNOS, as a synthesizer of nitric oxide (NO), plays an important role in the regulation of vascular tone, platelet and leukocyte adhesion to the endothelium, endothelin-1 generation, vascular smooth muscle proliferation, and vascular lesion formation. Recently, it has been demonstrated that eNOS directly binds to the 90 kDa heat shock proteins, Hsp90, however, the interacting domains in the two proteins have not been identified. Increased interaction of Hsp90 with eNOS has been demonstrated with a variety of treatments and is associated with increased eNOS activity, which can be blocked by the specific inhibitor of Hsp90, geldanamycin. The mechanism for Hsp90 activation of eNOS is unknown. Due to its role as a molecular chaperone, Hsp90 may stabilize and prevent the aggregation of partially folded or dimeric forms of eNOS, thereby increasing the overall activity. In addition, Hsp90 may alter the three dimensional structure of eNOS and affect binding of important co-factors such as calmodulin (CaM). Therefore, the goals of this project are two-fold, to map the interacting domains between Hsp90 and eNOS and to examine potential mechanisms by which Hsp90 upregulates eNOS activity.