Fig. 8

Schematic showing proposed mechanism. HOPE inhibits the three branches of UPR (PERK, ATF6, and IRE1 pathways) by activating JAK2/STAT3 signal pathway, thus alleviating ER stress and apoptosis. In addition, activated JAK2/STAT3 signal pathway can maintain ER calcium homeostasis by upregulating HAX1 and promoting the interaction of HAX1/SERCA2b. Upregulated HAX1 also regulates ER stress and apoptosis by inhibiting the IRE1 pathway