Considering several lines of evidence indicating that autophagy perturbation causes neurodegeneration (Mizushima & Levine, 2020) and our results showing that JIP4 KO cells are more vulnerable to acrolein treatment compared with parental cells, acrolein might act as a hormetic to enhance the defensive response via autophagy induction at the early stages of PD despite the high toxicity of this metabolite. Here, SPAG9 is linked to Parkinson disease.