SLC6A3 and early-onset autosomal dominant Alzheimer disease: In dopamine receptor signal transduction, PKC regulates numerous physiological functions, such as dopamine release, internalization of the dopamine transporter, downregulation of dopamine receptors, etc. In disease conditions, hyperactivation of PKC can lead to disorders such as schizophrenia and Parkinson’s disease, while reduced PKC signaling may be associated with Alzheimer’s disease.