(A–B) Representative Western blots (A) and quantifications
(B) of the synaptic abundance of the indicated proteins in P15 wild-type (WT) and Srgap2a KO brains (n=4).
(C) Immunofluorescence of endogenous proteins in cortical neurons cultured for 17–18 days in control condition (shControl) or after Srgap2a knock-down (shSrgap2). Scale bar 2 μm.
(D) Normalized fluorescence intensity (Norm. Fluo.) associated with clusters of the indicated proteins in shControl and shSrgap2 conditions (n=40–42 cells).
(E) Live imaging of SEP-GluA2 and SEP-γ2 GABAA receptors in control pyramidal neurons, after Srgap2a knock-kown or after SRGAP2C expression (20–22 days in vitro). Scale bar: 2 μm.
(F) Mean receptor cluster size in the conditions described above. SEP-GluA2: nshControl = 34, nshSrgap2 = 35, nSRGAP2C = 32 ; SEP-γ2: nshControl = 36, nshSrgap2 = 25, nSRGAP2C = 35. Mean ± SEM.
(G) Representative traces of mEPSCs in control (black) and shSrgap2-electroporated (red) neurons.
(H–I) Quantification of mEPSC amplitude (nControl = 2883 from 5 cells, nshSrgap2 = 2811 from 5 cells) and interevent intervals (nControl = 7232, nshSrgap2 = 6587). Cumul. Prob.: cumulative probability. Inset indicates the mean frequency per cell.
(J) Representative traces of mIPSCs in control (black) and shSrgap2-electroporated (red) neurons.
(K–L) Quantification of mIPSC amplitude (nControl = 4370 from 7 cells, nshSrgap2 = 4125 from 7 cells) and interevent intervals (nControl = 11520, nshSrgap2 = 8262). Inset indicates the mean frequency per cell.
*** p < 0.001, NS: p > 0.05, Mann-Whitney test or Kruskal-Wallis test followed by Dunn’s multiple comparison test (panel F).