We have previously shown that angiotensin-converting enzyme 2 (ACE2), an enzyme counterbalancing the deleterious effects of angiotensin type 1 receptor activation by production of vasodilatory peptides Angiotensin (Ang)-(1–9) and Ang-(1–7), is internalized and degraded in lysosomes following chronic Ang-II treatment. However, the molecular mechanisms involved in this effect remain unknown. In an attempt to identify the accessory proteins involved in this effect, we conducted a proteomic analysis in ACE2-transfected HEK293T cells. A single protein, fascin-1, was found to differentially interact with ACE2 after Ang-II treatment for 4 h. The interactions between fascin-1 and ACE2 were confirmed by confocal microscopy and co-immunoprecipitation. Overexpression of fascin-1 attenuates the effects of Ang-II on ACE2 activity. In contrast, downregulation of fascin-1 severely decreased ACE2 enzymatic activity. Interestingly, in brain homogenates from hypertensive mice, we observed a significant reduction of fascin-1, suggesting that the levels of this protein may change in cardiovascular diseases. In conclusion, we identified fascin-1 as an ACE2-accessory protein, interacting with the enzyme in an Ang-II dependent manner and contributing to the regulation of enzyme activity.

我们之前已经证明血管紧张素转换酶 2 (ACE2)，一种通过产生血管扩张肽血管紧张素 (Ang)-(1-9) 和 Ang-(1-7) 来抵消血管紧张素 1 型受体激活的有害作用的酶，在慢性 Ang-II 治疗后在溶酶体中内化和降解。然而，这种效应所涉及的分子机制仍然未知。为了确定参与这种效应的辅助蛋白，我们在 ACE2 转染的 HEK293T 细胞中进行了蛋白质组学分析。在 Ang-II 处理 4 小时后，发现一种蛋白质 fascin-1 与 ACE2 发生了不同的相互作用。通过共聚焦显微镜和免疫共沉淀证实了 fascin-1 和 ACE2 之间的相互作用。fascin-1 的过表达减弱了 Ang-II 对 ACE2 活性的影响。相比之下，fascin-1 的下调严重降低了 ACE2 酶的活性。有趣的是，在高血压小鼠的脑匀浆中，我们观察到 fascin-1 显着减少，这表明这种蛋白质的水平可能会在心血管疾病中发生变化。总之，我们将 fascin-1 鉴定为 ACE2 辅助蛋白，以依赖 Ang-II 的方式与酶相互作用并有助于调节酶活性。