PKD1 and Parkinson disease: Our study reports, for the first time, three key findings in an oxidative stress-induced dopaminergic degeneration model using 6-OHDA: (i) PKD1 activation occurs at an early stage of oxidative damage in cell culture models of PD, (ii) phosphorylation of Ser 916 residue regulates activation loop phosphorylation (PKD1- pS744/S748), and (iii) modulation of PKD1 signaling has protective effects against oxidative damage of dopaminergic cell death.