XBP1 and tauopathy: First, we used mild models of human wild type tau toxicity [Tau (low) transgenic C. elegans models]30,31 and found loss of function of XBP-1 and ATF-6 UPRER transcriptional branches enhanced tauopathy phenotypes, including exacerbated behavior defects, increased tau protein accumulation, and more severe neurodegeneration30.