FIGURE 10.

Schematic of dual protective effect flavonoids in RP associated with misfolding mutations in Rho. The substitution of Pro23, located in the Rho extracellular N-terminal loop, to His residue results in a structurally unstable receptor prone to aggregation in the endoplasmic reticulum (ER). An overload of misfolded protein induces the unfolded protein response (UPR) signaling and triggers reactive oxygen species (ROS) activation, which under continuous stress leads to the activation of cell death of photoreceptors. However, the binding of quercetin to the mutant Rho restores its WT-like conformation, which inhibits the UPR stress and prevents activation of photoreceptor cell death