Identification of protein kinase C phosphorylation sites within the AMPA receptor GluR2 subunit

Phosphorylation of AMPA receptor subunits is believed to regulate channel f unction and synaptic plasticity. Extensive biochemical and molecular studie s have identified sites of PKA. PKC and CamKII phosphorylation in the C-ter mini of the GluR1 and 4 subunits. Recent studies have shown GluR1 phosphory lation to be bidirectionally altered during long-term potentiation (LTP) an d long-term depression (LTD) in the hippocampus, The majority of AMPA recep tors in the brain are believed to contain the GluR2 subunit that also conta ins potential sites for protein phosphorylation. Here we characterize PKC p hosphorylation on the GluR2 subunit using biochemical and molecular techniq ues. Site-directed mutagenesis confirmed that this phosphorylation occurs o n Serine 863 and Serine 880 of the GluR2 subunit C-terminus. Site identific ation allowed the generation of phosphorylation site-specific antibodies to facilitate the examination of GluR2 modification in primary neuronal Cultu re. These studies confirmed that GluR2 is modified in response to the activ ation of PKC and suggests that phosphorylation of the ubiquitous GluR2 subu nit may be important in the regulation of excitatory synaptic transmission. (C) 2001 Elsevier Science Ltd. All rights reserved.