Required for learning most likely through its role in synaptic plasticity following NMDA receptor signaling. Interacts through its PDZ domains with NETO1 and APC. Interacts through its first two PDZ domains with ERBB4. Interacts through its third PDZ domain with NLGN1, and probably with NLGN2 and NLGN3 (By similarity). Interacts through its PDZ domains with GRIN2B and SYNGAP1. Interacts through its guanylate kinase-like domain with DLGAP1, DLGAP2, DLGAP3 and DLGAP4. Interacts with FRMPD4 (via C-terminus). Interacts with LRFN2. Interacts with LRFN1 and LRFN4. Interacts with FLTP (By similarity). Interacts with DGKI (via PDZ-binding motif) (PubMed:21119615). Belongs to the MAGUK family.