Figure 1.

Desensitized LiGluK2 Receptors Are Reversibly Trapped at Glutamatergic Synapses

(A) Schematic of SPT experiments: 488 nm and 380 nm light illumination was used to track receptors in the closed (blue) and desensitized (purple) states, respectively. A second 488-nm pulse induced recovery in the closed state (gray). The protocol was repeated five times every 2 min.

(B) Example trajectories (yellow) of the same individual LiGluK2 receptor diffusing at synapses (Homer1c, red) in the states described in (A). Scale bar, 1 μM.

(C and D) Summary of median diffusion coefficient (±IQR), immobile fraction, and MSD versus time curves of synaptic LiGluK2 (C) (n_trajectories = 140, in 10 neurons from three independent cultures) and extrasynaptic LiGluK2 (D) (n_trajectories = 250, in 10 neurons from three independent cultures) in the closed, desensitized, and recovery closed states.

(E) Schematic of SPT experiments as in (A), in the continued presence of VGCC blockers (2-APB, D-APV, ω-conotoxin MVIIC, GYKI 53655, nifedipine, and ryanodine; black) delivered after the initial 488-nm illumination (blue).

(F) Example trajectories (yellow) of an individual LiGluK2 receptor diffusing over a portion of dendrite (green) in the indicated states. Homer1c indicates synapses (red). Scale bar, 1 μM.

(G and H) Summary of median diffusion coefficient, immobile fraction, and MSD versus time curve of synaptic (G) and extrasynaptic (H) LiGluK2 in different states as indicated in (E) (n_trajectories: synaptic = 100; extrasyaptic = 206).

Unless otherwise stated, data are presented as mean ± SEM, ^∗p < 0.05; ^∗∗p < 0.01; ^∗∗∗p < 0.005; ns, non-significant. See also Figures S1 and S2.