The problem
Under stress, such as heat, cells can gather proteins and RNA messages into temporary stress granules. Most disperse when the stress ends. How are the ones that persist recognized and removed instead?[1]
After stress, some groups of RNA messages and proteins remain assembled instead of dispersing. How does the cell select these persistent stress granules for destruction while other assemblies dissolve? Such membraneless concentrations are condensates. In autophagy, membranes capture material and deliver it to lysosomes, compartments that break it down. Proteins called cargo receptors help connect selected material to this capture machinery. A 2026 study used a human neuroblastoma cell line engineered to express mutant FUS, an RNA-binding protein. Blocking the proteasome, another protein-disposal system, increased autophagic clearance of persistent granules under the tested conditions. That result does not identify the general selection rule.[1] [2]
Scope
Selective recognition and autophagic removal of persistent stress granules, distinguished from ordinary reversible granule dissolution.
What remains open
Why it matters
Dissolving a group frees its components; destroying it breaks material down. A cell that uses temporary assemblies needs to control both outcomes, making this part of how cells reorganize their molecules during and after stress.[1]
Stress granules gather RNA messages and proteins when protein production is disrupted, and many of the proteins continue to exchange with the surrounding cell. Their fate is therefore part of how a cell reorganizes its protein-making machinery during stress and afterward. In some persistent granules, proteins can form clumps that no longer dissolve readily. Understanding clearance would connect a temporary stress response with the control of lasting protein deposits, and help explain whether recovery releases molecules or breaks them down. This does not mean every persistent assembly is harmful.[1]
Definitions
3 terms
autophagy
Here, a route that captures cellular material in membrane structures and delivers it to lysosomes for breakdown.[1]
lysosome
A cellular compartment whose acidic interior and enzymes break down delivered material.[1]
condensate
A local concentration of interacting molecules without an enclosing membrane; stress granules are one example.[1]
Sources
- The autophagy of stress granules
Notes on The autophagy of stress granules
Reviews stress-granule dissolution versus autophagic destruction and open selective recognition/capture mechanisms.
- Proteasome inhibition by VR23 enhances autophagic clearance of FUSP525L-mediated persistent stress granule in SH-SY5Y cells
Notes on Proteasome inhibition by VR23 enhances autophagic clearance of FUSP525L-mediated persistent stress granule in SH-SY5Y cells
A mutant-FUS cell-line experiment supports altered autophagic granule clearance, with reporter and generalization limits.