Stress granules are ribonucleoprotein structures that form in cell cytoplasm under stress conditions.
Their function is still not completely clear, but it is known that stress response due to sublethal harsh conditions prevents cell death caused by otherwise lethal stimuli applied later. Whether the formation of granules is essential for this protective effect is not known.
Here we treated U2OS [osteosarcoma] cells with arsenite and stopped the noxious stimulus at different times.
- Then we immunostained with antibodies against eIF2alpha, which is known to accumulate in stress granules (green),
- red fluorescent phalloidin (which binds to actin filaments, allowing to see cell shape)
- and DAPI (a blue stain which binds DNA).
You can see how eIF2alpha is widespread in the cytoplasm under basal conditions, being recruited to stress granules when the cell is under harsh conditions.