The protein encoded by this gene is an auxiliary subunit of the ionotropic glutamate receptor of the AMPA subtype. AMPA receptors mediate fast synaptic neurotransmission in the central nervous system. This protein has been reported to interact with the Type I AMPA receptor regulatory protein isoform gamma-8 to control assembly of hippocampal AMPA receptor complexes, thereby modulating receptor gating and pharmacology. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Aug 2012].