Figure 4.

Activated CaMKII concentrates in spines both at the PSD and away from the PSD after NMDA receptor stimulation. A, Cells transfected with GFP-CaMKIIα and PSD-95-mCherry were imaged by confocal microscopy before and after NMDAR stimulation. Scale bar, 2 μm. B, Enlarged view from A (left) and other experiments before (right top) and after 0 Mg²⁺/Gly stimulation (right bottom). Scale bar, 1 μm. C, CaMKII localizations were binned (25 nm) to construct a map of CaMKII density under basal conditions and after Glu/Gly stimulation. Scale bar, 1 μm. D, CaMKII enrichment at the PSD was quantified in different cells under basal conditions and after Glu/Gly stimulation. *p < 0.05 (K-S test, n = 52 synapses for basal, n = 22 synapses for Glu/Gly). E, For basal condition and after Glu/Gly stimulation, image (top) shows density map of the spine from C (green) superimposed on deconvolved widefield image of PSD95-Cerulean3 (red). Lines indicate profiles along which intensity was measured, as shown in the graph (bottom). F, Quantification of the intensity of phospho-T286 immunostaining under basal conditions and after Glu/Gly stimulation. *p < 0.001 (K-S test, n = 11 cells). G, Example of phospho-T286 CaMKII (red) with the plasma membrane labeled with DiI (green) resolved by two-color localization microscopy. H, Example of phospho-T286 CaMKII as in G (red) with the PSD resolved by PALM of PSD-95-mEos2 (green). Scale bar, 1 μm.