PSD93 (postsynaptic density protein of 93 kDa, also called chapsin 110 and DLG 2) belongs to the PSD95 family containing a modular structure with three PDZ-, one SH3- and a guanylate kinase-like domain. It is a component of postsynaptic densities in central synapses.
PSD93 is expressed in discrete neuronal populations as well as in specific non-neuronal cells. It exhibits complex molecular diversity attributable to tissue-specific alternative splicing. PSD93, like PSD95, binds to NMDA receptors and to the neuronal nitric oxide synthase (NOS).
PSD93 and PSD95 can heteromultimerize with each other and are recruited into the same NMDA receptor and K+ channel clusters. PSD93, however, is unique among PSD95 family members in its expression in Purkinje neuron cell bodies and dendrites.