Structural impact of K63 ubiquitin on yeast translocating ribosomes under oxidative stress

Significance K63 ubiquitination of ribosomes serves as a key regulator of protein production during cellular exposure to oxidative stress. Defining the structural and functional mechanisms of translation regulation would support the current understanding of critical reprogramming of eukaryotic gene expression. Our paper presents an examination of the structure of K63 ubiquitinated ribosomes, revealing that this modification structurally destabilizes proteins involved in the binding of translation factors and is required to trap ribosomes at the pretranslocation stage of translation elongation. We provide evidence for a new redox regulatory mechanism of translation in which K63 ubiquitin aids the global repression of protein synthesis and is essential for coping with the harms of oxidative stress.