Neuregulin-1 Regulates Cortical Inhibitory Neuron Dendrite and Synapse Growth through DISC1

Figure 4

ErbB4 and DISC1 physically interact in cortical inhibitory neurons. (a) Co-IP of DISC1-GFP and ErbB4 in lysates from HEK293 FT cells transfected with ErbB4, ErbB4 KD, or DISC1-GFP alone or with DISC1-GFP + ErbB4 or DISC1-GFP + ErBb4 KD, with or without NRG1 treatment. Left panel: western blot for ErbB4 and DISC1-GFP in anti-GFP (DISC1) precipitates and input. Right panel: western blot for ErbB4 and DISC1-GFP in anti IgG control precipitates and input. DISC1-GFP binds ErbB4 in both PBS and NRG1 conditions (left panel, asterisks). Binding is reduced with DISC1-GFP and kinase dead ErbB4 (ErbB4 KD) (left panel). No binding was observed in the IgG control precipitates (right panel). (b) Proximity Ligation Assay (PLA) was performed in DIV21 cortical inhibitory neurons transfected with -GFP on DIV7 and treated with NRG1β or PBS for 5 min prior to fixation. Primary antibodies were omitted in the control PLA condition. Representative images were acquired at 63x. Scale bars = 10 μm. NRG1β treatment significantly increased the number of PLA signals in the cell body. Arrowheads indicate PLA signals colocalized with -GFP positive neurons (c) and the primary dendrites (d). Significance determined using a one-way analysis of variance (ANOVA) with Tukey’s post hoc tests. Error bars represent standard error of the mean, –15 cells (2-3 primary dendrites/cell) per condition from 3 experiments; , .

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