The membrane-bound transcription factor ATF6α plays a cytoprotective role in the unfolded protein response (UPR), required for cells to survive ER stress. Activation of ATF6α promotes cell survival in cancer models. We used cell-based screens to discover and develop Ceapins, a class of pyrazole amides, that block ATF6α signaling in response to ER stress. Ceapins sensitize cells to ER stress without impacting viability of unstressed cells. Ceapins are highly specific inhibitors of ATF6α signaling, not affecting signaling through the other branches of the UPR, or proteolytic processing of its close homolog ATF6β or SREBP (a cholesterol-regulated transcription factor), both activated by the same proteases. Ceapins are first-in-class inhibitors that can be used to explore both the mechanism of activation of ATF6α and its role in pathological settings. The discovery of Ceapins now enables pharmacological modulation all three UPR branches either singly or in combination.
膜结合转录因子
ATF6α 在未折叠蛋白反应(
UPR)中发挥细胞保护作用,是细胞在 ER 压力下存活的必要条件。激活
ATF6α 能促进癌症模型中细胞的存活。我们利用基于细胞的筛选发现并开发了Ceapins,这是一类
吡唑酰胺,能阻断
ATF6α在ER应激反应中的信号传导。Ceapins能使细胞对ER应激敏感,而不影响未应激细胞的存活率。Ceapins是
ATF6α信号传导的高度特异性
抑制剂,不会影响
UPR其他分支的信号传导,也不会影响其近源同源物
ATF6β或SREBP(一种
胆固醇调控转录因子)的蛋白
水解处理。Ceapins是第一类
抑制剂,可用于探索
ATF6α的激活机制及其在病理环境中的作用。Ceapins的发现使我们现在可以单独或联合对所有三个
UPR分支进行药理调节。