In an Apaf1 null background, Tg2576 mice did not activate caspase-3, suggesting involvement of the mitochondrial pathway.70 Other caspases, such as caspase-6 and the ER-resident caspase-4 are also associated with AD,77, 78 and activation of the ER stress pathway was observed in vivo and in vitro. Here, CASP3 is linked to Alzheimer disease.