HTT and Huntington disease: Proteasome sequestration in HD and is potentially a protective response to reduce huntingtin toxicity, as proteasome cleavage of mutant huntingtin can produce a highly aggregate prone degradation product (Jana et al., 2001; Diaz-Hernandez et al., 2004; Seo et al., 2004; Bowman et al., 2005; Bett et al., 2006).