Selective targeting of mRNA and the following protein synthesis of CaMKIIα at the long-term potentiation-induced site.

Late-phase long-term potentiation (L-LTP) in hippocampus, thought to be the cellular basis of long-term memory, requires new protein synthesis. Neural activity enhances local protein synthesis in dendrites, which in turn mediates long-lasting synaptic plasticity. Ca/calmodulin-dependent protein kinase IIα (CaMKIIα) is a locally synthesized protein crucial for this plasticity, as L-LTP is impaired when its local synthesis is eliminated. However, the distribution of mRNA during L-LTP induction remains unclear. In this study, we investigated the dendritic targeting of mRNA after high-frequency stimulation, which induces L-LTP in synapses of perforant path and granule cells in the dentate gyrus hybridization studies revealed that mRNA was immediately but transiently targeted to the site receiving high-frequency stimulation. This was associated with an increase in protein synthesis of CaMKIIα. These results suggest that dendritic translation of CaMKIIα is locally mediated where L-LTP is induced. This phenomenon may be one of the essential processes for memory establishment.