ABL1 and Parkinson disease: These studies were motivated by prior studies demonstrating that the levels of the activated form of c-Abl kinase, which phosphorylates aSyn efficiently at Y39135, are increased in the striatum and SN in PD brains136 and that an inhibitor of c-Abl increases aSyn clearance and is neuroprotective in preclinical models of PD137–140.