The FERM and PDZ domain containing (FRMPD) protein family consists of four proteins that contain a FERM (Four-point-one, erzin, radixin, moesin) domain and at least one PDZ (PSD-95/Discs large/Zonula-occuldens-1) domain. Unlike other members of the FRMPD family, FRMPD3 has no known function. It is most similar to FRMPD4, which is highly expressed in multiple regions of the brain and enriched in the postsynaptic density (PSD) fractions, it is possible that FRMPD3 also interacts with other PDZ domain-containing proteins in neural cells.