AKT1 and Parkinson disease: Data from literature show that total Akt and p-Akt (Serine473) is found at high levels in TH immunopositive dopaminergic neurons in human brain, and selective loss of these neurons is accompanied by a marked decrease of total Akt and p-Akt (Serine473) levels in the PD brain (Timmons et al., 2009).