“…Frozen cerebrum were weighted and mechanically homogenized in ice‐cold IP buffer: 150 mM NaCl (Cat# J21618, Millipore Sigma, St. Louis, Missouri); 10 mM Tris‐HCL, pH 7.4 (Cat# BP2471‐1, Thermo Fisher Scientific, Waltham, Massachusetts); 1 mM EDTA (Cat# BP118‐500, Thermo Fisher Scientific); 1 mM EGTA, pH 8.0 (Cat# E3889, Millipore Sigma); 0.2 mM sodium orthovanadate (Cat# S6508, Millipore Sigma); 0.2 mM PMSF (Cat# P7626, Millipore Sigma); 1% Triton X‐100 (Cat# X100, Millipore Sigma); 0.5% NP‐40 (Cat# 97063‐298, Amresco, LLC., Solon, Ohio), and centrifuged (10,000 g , 5 min, 4°C). Immunoprecipitations were performed on total protein adjusted to 1 mg/mL with IP buffer, as described by Fertan, et al 105 In brief, samples were precleared with protein A/G magnetic beads (Cat# 88802) and incubated on a nutator (4C, 1 hr) with antibodies specific for NLGN1 (Cat#: MBS9365594), NLGN2 (Cat#: MBS9915356), or MDGA2 (Cat#: MBS9717695) or nonimmune IgG (MyBioSource, San Diego, California). Immuno‐complexes were captured with Protein A beads on a nutator (4C, 1 hr) and the supernatant was discharged.…”