This gene encodes a protein that is an auxiliary subunit of the ionotropic glutamate receptor of the AMPA subtype. This protein is similar to a Drosophila protein involved in anterior-posterior and dorsal-ventral patterning. Cnih2 conditional knockout mice exhibit reduced AMPA receptor synaptic transmission in the hippocampus. Alternative splicing results in multiple transcript variants encoding different isoforms. [provided by RefSeq, Oct 2014]