SPHK2 and Parkinson disease: In particular, the role of S1P/SK2 pathway in regulating the survival of the dopaminergic neurons has emerged, suggesting that dysregulation of this pathway might be relevant to the clinical development of Parkinson’s disease (PD); in addition, a role for SK1 and SK2 has also been suggested in the onset of AD (Pyne et al., 2016).