Publication Type:Journal Article
Source:J Neurosci, Volume 32, Issue 31, p.10767-79 (2012)
Keywords:4-Aminopyridine, Analysis of Variance, Animals, Bicuculline, Calcium, Calcium-Calmodulin-Dependent Protein Kinase Type 2, Cells, Cultured, Cerebral Cortex, Dendritic Spines, Enzyme Inhibitors, Excitatory Amino Acid Antagonists, GABA-A Receptor Antagonists, Guanylate Kinase, Immunoprecipitation, In Vitro Techniques, Luminescent Proteins, Male, MAP Kinase Signaling System, Membrane Proteins, Mice, Mice, Inbred C57BL, Microtubule-Associated Proteins, Neuronal Plasticity, Neurons, Phosphorylation, Photobleaching, Potassium Channel Blockers, Rats, Receptors, N-Methyl-D-Aspartate, RNA, Small Interfering, Transfection
Understanding how brief synaptic events can lead to sustained changes in synaptic structure and strength is a necessary step in solving the rules governing learning and memory. Activation of ERK1/2 (extracellular signal regulated protein kinase 1/2) plays a key role in the control of functional and structural synaptic plasticity. One of the triggering events that activates ERK1/2 cascade is an NMDA receptor (NMDAR)-dependent rise in free intracellular Ca(2+) concentration. However the mechanism by which a short-lasting rise in Ca(2+) concentration is transduced into long-lasting ERK1/2-dependent plasticity remains unknown. Here we demonstrate that although synaptic activation in mouse cultured cortical neurons induces intracellular Ca(2+) elevation via both GluN2A and GluN2B-containing NMDARs, only GluN2B-containing NMDAR activation leads to a long-lasting ERK1/2 phosphorylation. We show that αCaMKII, but not βCaMKII, is critically involved in this GluN2B-dependent activation of ERK1/2 signaling, through a direct interaction between GluN2B and αCaMKII. We then show that interfering with GluN2B/αCaMKII interaction prevents synaptic activity from inducing ERK-dependent increases in synaptic AMPA receptors and spine volume. Thus, in a developing circuit model, the brief activity of synaptic GluN2B-containing receptors and the interaction between GluN2B and αCaMKII have a role in long-term plasticity via the control of ERK1/2 signaling. Our findings suggest that the roles that these major molecular elements have in learning and memory may operate through a common pathway.