Protein phosphatase 1 modulation of neostriatal AMPA channels: regulation by DARPP–32 and spinophilin

Modulation of AMPA–type glutamate channels is important for synaptic plasticity. Here we provide physiological evidence that the activity of AMPA channels is regulated by protein phosphatase 1 (PP–1) in neostriatal neurons and identify two distinct molecular mechanisms of this regulation. One mechanism involves control of PP–1 catalytic activity by DARPP–32, a dopamine– and cAMP–regulated phosphoprotein highly enriched in neostriatum. The other involves binding of PP–1 to spinophilin, a protein that colocalizes PP–1 with AMPA receptors in postsynaptic densities. The results suggest that regulation of anchored PP–1 is important for AMPA–receptor–mediated synaptic transmission and plasticity.