Myr‐C9orf72 transmembrane peptide attenuates abnormal autophagy, such as the downregulation of LC3II/I expression, upregulation of p62 and α‐synuclein expression, and dopaminergic neuron death and dyskinesia in PD by interfering with Cdk5 phosphorylation of the Ser9 site of C9orf72 protein. Here, CDK5 is linked to Parkinson disease.