Synaptic activity regulates the association of AMPARs with postsynaptic nanodomains. (A and B) Neurons were treated with 90 mM KCl for 5 min and recovered for 60 min. Neurons were analyzed by 2C-STED imaging of surface GluA1 (A, green pseudocolor) and hPF11 (A, red pseudocolor), and the maximum intensity of surface AMPARs on PF11-labeled nanodomains was measured (B). In total, ∼1,000 clusters from 8–12 neurons (two independent experiments) were analyzed. ***, P < 0.001 by one-way ANOVA with post-hoc Tukey’s test. Bar, 500 nm. (C) A DHHC2-mediated subdomain model for PSD (re)organization: organization of nanodomains through local palmitoylation/depalmitoylation cycles. See Discussion.