Protein Phosphatase 1, Regulatory Subunit 1B (PPP1R1B)

Midbrain dopaminergic neurons play a critical role in multiple brain functions, and abnormal signaling through dopaminergic pathways has been implicated in several major neurologic and psychiatric disorders. In the densely dopamine- and glutamate-innervated rat caudate-putamen, DARPP32 is expressed in medium-sized spiny neurons that also express dopamine D1 receptors. The function of DARPP32 seems to be regulated by receptor stimulation. Both dopaminergic and glutamatergic (NMDA) receptor stimulation regulate the extent of DARPP32 phosphorylation, but in opposite directions. Dopamine D1 receptor stimulation enhances cAMP formation, resulting in the phosphorylation of DARPP32; phosphorylated DARPP32 is a potent protein phosphatase-1.