Research

Dr. Wei Wang published a paper in Molecular Plant.

Cellular oxidation is essential for many physiological processes but can damage redox-vulnerable proteins. Eukaryotic cells maintain millimolar levels of reduced glutathione (GSH) as a major antioxidative strategy. However, how this highly reduced pool is locally reorganized to permit necessary oxidation without triggering proteolysis remains unclear. Here, we show that protein S-glutathionylation promotes stress granule (SG) assembly, creating reductive microenvironments within an oxidized cytosol to protect redox-sensitive proteins and modulate GSH biosynthesis during salicylic acid (SA)–induced oxidative stress in Arabidopsis thaliana. SA enhanced GSH oxidation and protein glutathionylation both in vitro and in vivo. To visualize glutathionylated proteins under native conditions, we developed CamLog, a transgene-free click-activated metabolic labeling method. CamLog revealed that SA induces glutathionylated protein condensates that strongly overlap with SG markers but not with processing bodies. These condensates share more than 77% of their components with SGs, with translation-related proteins particularly enriched, and pharmacological analyses confirmed their identity as oxidative-stress-induced SGs. Glutathionylation of the SG marker RBP47B regulated its mobility and SA responsiveness, and global inhibition of glutathionylation abolished SG formation. Conversely, SGs sequestered glutathionylated proteins, including translation machinery, forming a reductive niche that prevents oxidation-induced proteolysis. SGs also sequestered GSH1, the rate-limiting enzyme for GSH biosynthesis, suggesting a mechanism to fine-tune GSH metabolism rather than fully counteract oxidation. Together, our findings uncover an organelle-level role of SGs in shaping cytosolic redox heterogeneity and highlight a spatial antioxidative strategy relevant to oxidation-vulnerable systems.

Original link: https://doi.org/10.1016/j.molp.2025.12.018