Apratoxin S4 (Apra S4), a potent inhibitor of Sec61, disrupts the cotranslational translocation of secretory proteins into the endoplasmic reticulum (ER), showcasing antiviral efficacy against select flaviviruses with IC 50 values spanning 0.46 nM to 170 nM. It also curtails retinal vascular cell activation by targeting various angiogenic pathways. This compound is valuable for investigating viral infections, angiogenic diseases, and cancers [1] [2].