Higher levels of ATF6 and p-eIF2α in the motor neurons of transgenic SOD1G93A mice has further substantiated the involvement of UPR in ALS, although the levels of spliced XBP1 or sXBP1 (a downstream marker of the UPR/IRE1 pathway) are not significantly different [175]. Here, XBP1 is linked to amyotrophic lateral sclerosis.