Working hypothesis for how formation of CaMKII/NMDAR complex during LTP induction leads to subsequent binding reactions necessary for late LTP. A, Before LTP induction (some NMDA channels have no CaMKII bound). B, During LTP induction, CaMKII is activated and forms a persistent complex with the NMDA channel, thus forming a tag. C, This serves as a structural seed for the gradual capture of densin, delta-catenin, ABP, and N-cadherin (cad). The addition of ABP provides additional anchoring sites for AMPA channels, thereby strengthening transmission. The binding of additional N-cadherin (which is synthesized in response to activity) enlarges the synapse both presynaptically and postsynaptically.