Metabotropic glutamate receptor-initiated translocation of protein kinase p90rsk to polyribosomes: A possible factor regulating synaptic protein synthesis

Maintenance of lasting synaptic efficacy changes requires protein synthesis . We report here a mechanism that might influence translation control at th e level of the single synapse. Stimulation of metabotropic glutamate recept ors in hippocampal slices induces a rapid protein kinase C-dependent transl ocation of multifunction kinase p90rsk to polyribosomes; concomitantly, the re is enhanced phosphorylation of at least six polyribosome binding protein s. Among the polyribosome bound proteins are the p90rsk-activating kinase E RK-2 and a known p90rsk substrate, glycogen synthase kinase 3 beta, which r egulates translation efficiency via eukaryotic initiation factor 2B. Thus m etabotropic glutamate receptor stimulation could induce synaptic activity-d ependent translation via translocation of p90rsk to ribosomes.