Phosphorylation of serine-880 in GluR2 by protein kinase C prevents its C terminus from binding with glutamate receptor-interacting protein

Phosphorylation of the glutamate receptor is an important mechanism of syna ptic plasticity. Here, we show that the C terminus of GluR2 of the alpha-am ino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptor is phosphoryla ted by protein kinase C and that serine-880 is the major phosphorylation si te. This phosphorylation also occurs in human embryonic kidney (HEK) cells by addition of 12-O-tetradecanoylphorbol 13-acetate. Our immunoprecipitatio n experiment revealed that the phosphorylation of serine-880 in GluR2 drast ically reduced the affinity for glutamate receptor-interacting protein (GRI P), a synaptic PDZ domain-containing protein, in vitro and in HEK cells. Th is result suggests that modulation of serine-880 phosphorylation in GluR2 c ontrols the clustering of AMPA receptors at excitatory synapses and consequ ently contributes to synaptic plasticity.