These results agree with others that RTP801 degradation depends on the UPS.21, 22, 23 UPS alterations are a common feature in cellular and animal models of PD and in the disease itself.34, 35 Based on our results, UPS impairment associated with PD could contribute, in part, to RTP801 elevation in both sporadic PD and AR-JP. Here, DDIT4 is linked to Parkinson disease.