According to a new study, nutrient-starved cells divert protein transport stations to cellular recycling centres to be broken down, highlighting a novel approach cells use to deal with stressful conditions.
The endoplasmic reticulum (ER), a snaking membrane within the cell, produces new proteins destined for the outside world. Grape-like tubular outgrowths on the ER known as ER exit sites act as transport stations, collecting freshly synthesised proteins and transferring them to the next step in their trip.
In recent years, scientists have discovered that these ER exit sites also help deliver cellular material and misfolded proteins to lysosomes — organelles that degrade and recycle material in the cell — and provide a platform for replication of viruses, including COVID-19. But researchers were perplexed how this one structure, the ER exit site, can participate in all these diverse functions.