UCHL1 and Alzheimer disease: Interestingly, the neuron specific DUB ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1)—one of the most abundant proteins in the brain—is downregulated in sporadic AD brains (Choi et al., 2004) and its activity is reduced in the hippocampus of AD mice (Gong et al., 2006) providing strong evidence linking UCH-L1 to the pathogenesis of AD.