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.

Belongs to the MAGUK family.
Contains 1 guanylate kinase-like domain.
Contains 3 PDZ (DHR) domains.
Contains 1 SH3 domain.

An N-terminally truncated L27 domain is predicted in isoform 2 at positions 1 through 27.

Palmitoylation of isoform 1 is not required for targeting to postsynaptic density.

Cell membrane. Cell junction, synapse, postsynaptic cell membrane, postsynaptic density. Cell junction, synapse. Membrane. Cell projection, axon. Concentrated in soma and postsynaptic density of a subset of neurons.