Conclusion
The signaling pathway identified in this work, together with its conserved components, provides valuable clues for understanding the mechanisms underlying SG formation and SG-associated human diseases.
Methods
By performing two high-content imaging-based phenomic screens, we identified multiple signaling components that form a possible signal transduction pathway that regulates SG formation.
Results
We found that Sch9 and Ypk1 function in an early step of SG formation, leading to a decrease in intermediate long-chain base sphingolipids (LCBs). This further downregulates the polyubiquitin precursor protein Ubi4 through upregulating the deubiquitinase Ubp3. Decreased levels of cellular free ubiquitin may subsequently facilitate Lsm7 phase separation and thus trigger SG formation.