Notably, the phosphorylated form of Psmc5/Rpt6 has been proposed as a marker for monitoring proteasomal activity in the aging rat brain36, and the decreased expression of PSMC5 as a potential biomarker for the onset or development of Parkinson’s disease, Lewy body dementia or Alzheimer’s disease60–62. The gene discussed is PSMC5; the disease is Parkinson disease.