CDK5 and Parkinson disease: Quantitative phosphoproteomic analysis of α-synuclein transgenic mice showed that elevated Cdk5/p25 pathway activity contributed to SNpc dopaminergic neuronal death in model mice (Stillwell and Myers, 1988), which was also observed in mice administrated with 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP), a toxin used to induce PD model through destroying the nigrostriatal dopaminergic pathway (Binukumar et al., 2015).