Enables GABA receptor binding activity and ionotropic glutamate receptor binding activity. Involved in several processes, including gamma-aminobutyric acid receptor clustering; positive regulation of long-term synaptic potentiation; and regulation of signaling receptor activity. Located in asymmetric, glutamatergic, excitatory synapse and postsynaptic density. Is integral component of postsynaptic specialization membrane. Is expressed in central nervous system; craniocervical region bone; dorsal root ganglion; rib; and tail mesenchyme. Orthologous to human SHISA7 (shisa family member 7). [provided by Alliance of Genome Resources, Apr 2022]