…of the most abundant synaptic proteins, Ca2+/calmodulindependent protein kinase II (CaMKII), is concentrated at postsynaptic densities (PSDs) in spines (Kennedy et al., 1983), along with downstream substrates, including NMDA receptors (NMDA-Rs) and AMPA-receptors (AMPA-Rs) (Yoshimura et al., 2000).