EIF2AK2 and Huntington disease: PKR directly regulates tau, and activation of PKR has been associated with different tauopathies such as AD, Parkinson’s disease, and Huntington’ disease (Peel et al., 2001; Chang et al., 2002; Bando et al., 2005; Paquet et al., 2012; Lourenco et al., 2013; Ma et al., 2013).