Rabbit Anti-Human PSD93 monoclonal antibody for ICC, IF, WB. PSD-93, also known as chapsyn-110, is one of a family of plasma membrane-associated proteins found in synaptic junctions. PSD-93 is unique among family members in its expression in Purkinje neuron cell bodies and dendrites. PSD-93 has three ~90 amino acid repeats called PDZ domains, a single interior SH3 domain, and a carboxyl-terminal guanylate kinase homology (GuK) domain that is enzymatically inactive. It is hypothesized that PDZ-domain interactions play a role in receptor and channel clustering which contributes to neuronal plasticiyt. PSD-93 is believed to participate in the clustering of certain proteins, including NMDA receptors and shaker-type potassium channels at the synaptic membrane. There are two principal modes of interaction between PSD-93 and other proteins. NMDA receptors and shaker-type potassium channels both share C-terminal sequence homology consisting of a threonine/serine-X-valine-COOH (T/SXV) motif. Other neuronal proteins that share this motif may interact with PSD-93 by binding to its PDZ domains. Neuronal nitric oxide synthase (nNOS), which lacks the T/SXV motif but which has its own PDZ domain, has been shown to associate with PSD-93 in vitro through a pseudo-homotypic PDZ-PDZ interaction.