PSD 93 is believed to participate in the clustering of certain proteins, including N-methyl-D-aspartate (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 (beta 1 adrenergic receptor, some se