The postsynaptic proteome of excitatory synapses is physically organised into multiprotein complexes of which the supercomplexes assembled by PSD95 (Husi et al., 2000; Frank et al., 2016a; Frank and Grant, 2017; Frank et al., 2017) play a major role in regulating cognitive functions (Migaud et al., 1998; Nithianantharajah et al., 2013) and are disrupted by schizophrenia mutations (Pocklington et al., 2015; Fromer et al., 2014; Fernández et al., 2009a; Singh et al., 2017; Kirov et al., 2012; Purcell et al., 2014). This evidence concerns the gene DLG4 and schizophrenia.