ATXN3 and neurodegenerative disease: gp78 is highly involved in the degradation of neurodegenerative disease proteins and its substrates are known to include the aggregate-prone proteins SOD1, Ataxin-3, mutant Huntingtin and CFTRΔF508 (Yang et al., 2007, Yang et al., 2010, Ying et al., 2009, Ballar et al., 2011).