Since the XBP1 pathway fails to respond to protein-misfolding stress in PD iPSn20 (Fig. 3C, G), and many studies have shown that ER-Golgi trafficking is perturbed in PD models9,13,15–18,51, it is possible that failure of the UPR occurs through blocking ATF6 trafficking. Here, ATF6 is linked to Parkinson disease.