Messenger RNA

Eukaryotic Ribosome

Translation (biology)

Ribosome profiling

Biology

Gene

Ubiquitin ligase

Ubiquitin

Internal ribosome entry site

Cell biology

Genetics

Ribosome

Molecular Cell

Highlights•ZNF598 is a direct sensor of ribosome collisions incurred by many unrelated causes•The minimal target recognized and ubiquitinated by ZNF598 is a collided di-ribosome•Collided di-ribosome structure shows that ZNF598 ubiquitin sites are near the interface•Collisions are required to terminally arrest translation in ZNF598-dependent mannerSummaryAberrantly slow translation elicits quality control pathways initiated by the ubiquitin ligase ZNF598. How ZNF598 discriminates physiologic from pathologic translation complexes and ubiquitinates stalled ribosomes selectively is unclear. Here, we find that the minimal unit engaged by ZNF598 is the collided di-ribosome, a molecular species that arises when a trailing ribosome encounters a slower leading ribosome. The collided di-ribosome structure reveals an extensive 40S-40S interface in which the ubiquitination targets of ZNF598 reside. The paucity of 60S interactions allows for different ribosome rotation states, explaining why ZNF598 recognition is indifferent to how the leading ribosome has stalled. The use of ribosome collisions as a proxy for stalling allows the degree of tolerable slowdown to be tuned by the initiation rate on that mRNA; hence, the threshold for triggering quality control is substrate specific. These findings illustrate how higher-order ribosome architecture can be exploited by cellular factors to monitor translation status.Graphical abstract

ZNF598 Is a Quality Control Sensor of Collided Ribosomes