Postsynaptic MAGUK scaffold protein that links CADM1 cell adhesion molecules to core components of the postsynaptic density (By similarity). In CA1 pyramidal neurons, required for synaptic KCNN2-containing channel function and long-term potentiation expression (PubMed:26880549). Seems to negatively regulate SRC function in epithelial cells (By similarity). Can homomultimerise. Interacts with CACNG2. Interacts (via the SH3-Guanylate kinase-like sub-module) with DLG4/PSD95 and DLGAP1/GKAP. Interacts (via the PDZ domain) with CADM1 (via C-terminus) (By similarity). Interacts with KCNN2/SK2 (via N-terminal domain) (PubMed:26880549). Interacts with SRC (By similarity). Prominently expressed in the postsynaptic densities of dendritic spines, is also detected in dendritic shafts. Expressed in pyramidal neurons of CA1 region of the hippocampus. Phosphorylated by SRC. Belongs to the MAGUK family.