Functions as a scaffold protein and likely plays a role in N- methyl-D-aspartic acid receptor (NMDAR)-mediated synaptic excitatory transmission (By similarity). May be involved in synapse formation in cone photoreceptor cells (By similarity). May play a role in the regulation of tight junction formation (PubMed:19706687). Binds phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)P2) (PubMed:19706687). May play a role in the regulation of NOD2-mediated NF-kappa-B activation in immune response (PubMed:23213202). {ECO:0000250|UniProtKB:A0A140LI67, ECO:0000269|PubMed:19706687, ECO:0000269|PubMed:23213202}. This is the function of FRMPD2 (FERM and PDZ domain containing 2, Ensembl gene identifier ENSG00000170324).