LAP3 and Parkinson disease: Post-mortem data obtained from sporadic PD indicated structural and functional defects in the 26/20S proteasome, including loss of 20S core α-subunits (McNaught et al., 2002a; Grunblatt et al., 2004; Bukhatwa et al., 2010), loss of 19S regulatory particles, including the proteasomal activator PA700 (McNaught et al., 2003; Grunblatt et al., 2004), as well as a general loss of all three peptidase activities of the 20S proteasome (McNaught and Jenner, 2001; Tofaris et al., 2003).