Enables several functions, including PDZ domain binding activity; ionotropic glutamate receptor binding activity; and kinesin binding activity. Involved in several processes, including cell adhesion; neurotransmitter receptor localization to postsynaptic specialization membrane; and positive regulation of potassium ion transport. Located in several cellular components, including basolateral plasma membrane; lateral plasma membrane; and paranode region of axon. Is active in glutamatergic synapse and postsynaptic density, intracellular component. Biomarker of Parkinson's disease. Human ortholog(s) of this gene implicated in invasive ductal carcinoma. Orthologous to human DLG1 (discs large MAGUK scaffold protein 1). [provided by Alliance of Genome Resources, Apr 2022]