By crossing erp-44.3 (−/−) into the Tau (high); xbp-1s Tg background, we showed loss of function of erp-44.3 blocked xbp-1s-mediated suppression of tau-induced locomotion deficits, while erp-44.3 loss of function in the Tau (high) background did not change locomotion compared to Tau (high) animals alone (Fig. 6a), indicating erp-44.3 is also required for xbp-1s-mediated tauopathy suppression. Here, MAPT is linked to tauopathy.