This gene encodes a member of the membrane-associated guanylate kinase (MAGUK) family. The encoded protein forms a heterodimer with a related family member that may interact at postsynaptic sites to form a multimeric scaffold for the clustering of receptors, ion channels, and associated signaling proteins. Multiple transcript variants encoding different isoforms have been found for this gene. Additional transcript variants have been described, but their full-length nature is not known. [provided by RefSeq, Dec 2008],domain:Isoform 2 has an L27 domain close to N-terminus.,function:Required for perception of chronic pain through NMDA receptor signaling. Regulates surface expression of NMDA receptors in dorsal horn neurons of the spinal cord. Interacts with the cytoplasmic tail of NMDA receptor subunits as well as inward rectifying potassium channels. Involved in regulation of synaptic stability at cholinergic synapses. Part of the postsynaptic protein scaffold of excitatory synapses.,PTM:Palmitoylation of isoform 1 is not required for targeting to postsynaptic density.,similarity:Belongs to the MAGUK family.,similarity:Contains 1 guanylate kinase-like domain.,similarity:Contains 1 SH3 domain.,similarity:Contains 3 PDZ (DHR) domains.,subcellular location:Concentrated in soma and postsynaptic density of a subset of neurons.,subunit:Interacts with NOS1/nNOS through second PDZ domain (By similarity). Interacts with C-terminus of KCNJ2/Kir2.1 through one of its PDZ domains.,