Center for Genomics and Systems Biology , New York University , 12 Waverly Place , New York , New York 10003 , United States.
Department of Biology , Duke University , 130 Science Drive , Durham , North Carolina 27708 , United States.
J Proteome Res. 2019 Jan 4;18(1):309-318. doi: 10.1021/acs.jproteome.8b00623. Epub 2018 Dec 10.
During oxidative stress, K63-linked polyubiquitin chains modify a variety of proteins including ribosomes. Knowledge of the precise sites of K63 ubiquitin is key to understand its function during the response to stress. To identify the sites of K63 ubiquitin, we developed a new mass spectrometry based method that quantified >1100 K63 ubiquitination sites in yeast that responded to oxidative stress induced by HO. We determined that under stress, K63 ubiquitin-modified proteins were involved in several cellular functions including ion transport, protein trafficking, and translation. The most abundant ubiquitin sites localized to the head of the 40S subunit of the ribosome, modified assembled polysomes, and affected the binding of translation factors. The results suggested a new pathway of post-initiation control of translation during oxidative stress and illustrated the importance of high-resolution mapping of noncanonical ubiquitination events.
在氧化应激过程中，K63 连接的多泛素链修饰了包括核糖体在内的多种蛋白质。了解 K63 泛素的精确位点对于理解其在应激反应中的功能至关重要。为了确定 K63 泛素的位点，我们开发了一种新的基于质谱的方法，该方法定量检测了酵母中超过 1100 个对 HO 诱导的氧化应激有反应的 K63 泛素化位点。我们发现，在应激条件下，K63 泛素修饰的蛋白质参与了多种细胞功能，包括离子转运、蛋白质运输和翻译。最丰富的泛素位点定位于核糖体 40S 亚基的头部，修饰组装的多核糖体，并影响翻译因子的结合。结果表明，在氧化应激过程中存在一种新的翻译起始后调控途径，并说明了高分辨率绘制非典型泛素化事件的重要性。
