Scientists at Ludwig-Maximilians-Universität München have discovered that ribosomes, best known for their part in creating proteins, also act as a built-in alarm system that monitors cellular health. When normal protein production is interrupted by stressors like damaged messenger RNA, nutrient shortages, or viral infection, ribosomes can stall and collide with one another. These collisions are not a coincidence. Instead, they serve as a danger signal that activates a protective pathway inside the cell known as the ribotoxic stress response.
Researchers were able to find that a key protein called ZAK senses these ribosome collisions. When ZAK binds to the stalled ribosomes, it becomes activated and triggers a chain of molecular signals that helps the cell respond to the stress. Depending on how severe the damage is, the cell might attempt to repair itself, slow down protein production, or initiate programmed cell death to prevent further harm. Using advanced imaging techniques like cryo-electron microscopy, the team was able to analyze how ZAK interacts with collided ribosomes at the molecular level.
This discovery alters the way scientists understand ribosomes, revealing that they are not just protein factories but also significant sensors of cellular stress. Through showing how cells detect internal damage so quickly, the study provides new insight into how stress responses, inflammation, and disease development may be regulated. These findings could eventually contribute to new therapeutic strategies for conditions linked to chronic cellular stress or abnormal protein production.
https://www.cell.com/molecular-cell/fulltext/S1097-2765(20)30189-1
