ABSTRACT
The strength and duration of extracellular dopamine concentrations are regulated by the presynaptic dopamine transporter (DAT) and dopamine D2 autoreceptors (D2autoRs). There is a functional interaction between these two proteins. Activation of D2autoRs increases DAT trafficking to the surface whereas disruption of this interaction compromises activities of both proteins and alters dopaminergic transmission. Previously we reported that DAT expression and activity are subject to modulation by protein kinase Cß (PKCß). Here, we further demonstrate that PKCß is integral for the interaction between DAT and D2autoR. Inhibition or absence of PKCß abolished the communication between DAT and D2autoR. In mouse striatal synaptosomes and transfected N2A cells, the D2autoR-stimulated membrane insertion of DAT was abolished by PKCß inhibition. Moreover, D2autoR-stimulated DAT trafficking is mediated by a PKCß-extracellular signal-regulated kinase signaling cascade where PKCß is upstream of extracellular signal-regulated kinase. The increased surface DAT expression upon D2autoR activation resulted from enhanced DAT recycling as opposed to reduced internalization. Further, PKCß promoted accelerated DAT recycling. Our study demonstrates that PKCß critically regulates D2autoR-activated DAT trafficking and dopaminergic signaling. PKCß is a potential drug target for correcting abnormal extracellular dopamine levels in diseases such as drug addiction and schizophrenia.