PTK2 and Parkinson disease: SHP2 was shown to suppress neurite outgrowth by attenuating the activation of focal adhesion kinase (FAK), downstream of the LRRK2 gene, through direct binding to and dephosphorylation of pTyr397-FAK.69 SHP2 also had an anti-inflammatory effect through negative regulation of JAK/STAT signaling, a proinflammatory signaling pathway in the brain.70 By contrast, SHP2 positively affected the development of PD in levodopa-induced dyskinesia.