Enables ionotropic glutamate receptor binding activity. Involved in positive regulation of AMPA receptor activity and response to cocaine. Located in cell body; cell surface; and postsynaptic density membrane. Part of AMPA glutamate receptor complex. Is active in glutamatergic synapse. Is integral component of postsynaptic density membrane. Orthologous to human CACNG4 (calcium voltage-gated channel auxiliary subunit gamma 4). [provided by Alliance of Genome Resources, Apr 2022]