USP14 and Ataxia: The ataxia mice axJ, with a loss-of-function mutation in the UPS-associated deubiquitinating enzyme Usp14 show severe defects of the neuromuscular junction with impaired presynaptic function (Wilson et al., 2002; Chen et al., 2009) which are rescued by restoration of intracellular ubiquitin levels (Chen et al., 2011).