ATXN3 and Machado-Joseph disease: The Ubiquitin C-terminal Hydrolases (UCH), Ubiquitin Specific Proteases (USP), Machado-Joseph Disease Proteases (MJD), and Otubain (OTU) Proteases are cysteine proteases, while JAB1/MPN/Mov34 Metallo-enzyme (JAMM) proteases are zinc-dependent metallo-proteases (Figure 2).