Niskanen Einari A, Palvimo Jorma J
University of Eastern Finland, Institute of Biomedicine, Kuopio, Finland.
Bioessays. 2017 Jun;39(6). doi: 10.1002/bies.201600263. Epub 2017 Apr 25.
Post-translational modifications, e.g. SUMO modifications (SUMOylation), provide a mechanism for swiftly changing a protein's activity. Various stress conditions trigger a SUMO stress response (SSR) - a stress-induced rapid change in the conjugation of SUMO to multiple proteins, which predominantly targets nuclear proteins. The SSR has been postulated to protect stressed cells by preserving the functionality of crucial proteins. However, it is unclear how it exerts its protective functions. Interestingly, heat stress (HS) increases SUMOylation of proteins at active promoters and enhancers. In promoters, HS-induced SUMOylation correlates with gene transcription and stress-induced RNA polymerase II (Pol2) pausing. Conversely, a disappearance of SUMOylation in HS occurs at chromatin anchor points that maintain chromatin-looping structures and the spatial organisation of chromatin. In reviewing the literature, we hypothesise that the SSR regulates Pol2 pausing by modulating the interactions of pausing-regulating proteins, whereas deSUMOylation alters the function of chromatin anchors.
翻译后修饰，例如小泛素样修饰物修饰（SUMO化），提供了一种快速改变蛋白质活性的机制。各种应激条件会触发SUMO应激反应（SSR）——一种应激诱导的SUMO与多种蛋白质结合的快速变化，其主要作用于核蛋白。据推测，SSR通过保留关键蛋白质的功能来保护应激细胞。然而，尚不清楚它是如何发挥其保护功能的。有趣的是，热应激（HS）会增加活跃启动子和增强子处蛋白质的SUMO化。在启动子中，HS诱导的SUMO化与基因转录和应激诱导的RNA聚合酶II（Pol2）暂停相关。相反，HS中SUMO化的消失发生在维持染色质环结构和染色质空间组织的染色质锚点处。在回顾文献时，我们假设SSR通过调节暂停调节蛋白的相互作用来调节Pol2暂停，而去SUMO化则改变染色质锚点的功能。
