In addition to the NRG2 antibodies described above, the commercial and custom antibodies against the following proteins were used in this study: ErbB4, mouse monoclonal Ab-77 (Thermo Fisher; 1 μg/ml), rabbit monoclonal mAB10 (1 μg/ml) 7 (link) and rabbit polyclonal custom antibody 5721 (unpublished; 0.4 μg/ml); Kv2.1, mouse monoclonal (clone K89/34; NeuroMab; 1 μg/ml); rabbit polyclonal antibody against NRG1 (SC-348; Santa Cruz Biotechnology; 0.2 μg/ml); anti-V5 epitope tag (AbD Serotech; 1 μg/ml); Bassoon, rabbit polyclonal (Synaptic Systems; 1:1,000); Gephyrin, mouse monoclonal (clone mAb7a; Synaptic Systems; 1:500); PSD95, mouse monoclonal (clone 7E3-1B8; Pierce; 1:500); Calbindin, mouse monoclonal (clone CB-955; Sigma; 1:1,000); GFP, rabbit polyclonal (Molecular Probes; 1:2,000); Erk2, rabbit polyclonal (C-14; Santa Cruz; 0.2 μg/ml); phospho-Erk2, mouse monoclonal (clone E-4; Santa Cruz; 0.2 ug/ml); GAPDH, mouse monoclonal (clone 6C5; Santa Cruz; 0.2 μg/ml); clathrin heavy chain (CHC), mouse monoclonal (SC-12734; Santa Cruz; 0.1 μg/ml); GluN2A, rabbit monoclonal (clone A12W; Millipore; 1:2,000); GluN2B (clone 13; BD Biosciences; 1 μg/ml); GluA1 (AB1504; Millipore; 0.2 μg/ml).