Proteasome activity, particularly the chymotrypsin-like (CT-like) activity mediated by the β5 catalytic subunit encoded by Proteasome Subunit Beta Type-5 (PSMB5), has been shown to decline with age and in the context of PD [7–9] and other neurodegenerative diseases [10, 11]. The gene discussed is PSMB5; the disease is neurodegenerative disease.