The GRIK4 gene encodes a protein that forms a functional heteromeric ligand-gated ionic channel along with the subunits encoded by the GRIK1, GRIK2 and GRIK3 genes. This channel functions as a kainate receptor which is activated by the major excitatory neurotransmitter, glutamate. By carrying out its function, the GRIK4 kainate receptor contributes to excitatory post-synaptic currents in the central nervous system.
Recent studies in evolutionary biology have further implicated the role of GRIK4 in the development of the nervous system. This was indicated by the significantly higher rates of GRIK4 protein evolution in primates than in rodents. The acceleration of GRIK4 evolution was particularly pronounced in the lineage leading from ancestral primates to humans, which correlates with the phenotypic evolution of the human nervous system into a larger and more complex structure.