The influenza NS1 protein is involved in suppression of the host immune response. Recently, there is growing evidence that prion-like protein aggregation plays an important role in cellular signaling and immune responses. In this work, we obtained a recombinant, influenza A NS1 protein and showed that it is able to form amyloid-like fibrils in vitro. Using proteolysis and subsequent mass spectrometry, we showed that regions resistant to protease hydrolysis highly differ between the native NS1 form (NS1-N) and fibrillar form (NS1-F); this indicates that significant structural changes occur during fibril formation. We also found a protein fragment that is capable of inducing the process of fibrillogenesis at 37 °C. The discovery of the ability of NS1 to form amyloid-like fibrils may be relevant to uncovering relationships between influenza A infection and modulation of the immune response.

流感 NS1 蛋白参与抑制宿主免疫反应。最近，越来越多的证据表明朊病毒样蛋白聚集在细胞信号传导和免疫反应中起重要作用。在这项工作中，我们获得了一种重组的甲型流感 NS1 蛋白，并表明它能够在体外形成淀粉样蛋白样原纤维. 使用蛋白水解和随后的质谱分析，我们发现抗蛋白酶水解的区域在天然 NS1 形式 (NS1-N) 和纤维形式 (NS1-F) 之间存在很大差异。这表明在原纤维形成过程中发生了显着的结构变化。我们还发现了一种能够在 37°C 下诱导原纤维形成过程的蛋白质片段。发现 NS1 形成淀粉样蛋白原纤维的能力可能与揭示甲型流感感染与免疫反应调节之间的关系有关。