Important modulator of glutamate signaling pathway. Component of the outer core of AMPAR complex. AMPAR complex consists of an inner core made of 4 pore-forming GluA/GRIA proteins (GRIA1, GRIA2, GRIA3 and GRIA4) and 4 major auxiliary subunits arranged in a twofold symmetry. One of the two pairs of distinct binding sites is occupied either by CNIH2, CNIH3 or CACNG2, CACNG3. The other harbors CACNG2, CACNG3, CACNG4, CACNG8 or GSG1L. This inner core of AMPAR complex is complemented by outer core constituents binding directly to the GluA/GRIA proteins at sites distinct from the interaction sites of the inner core constituents. Outer core constituents include at least PRRT1, PRRT2, CKAMP44/SHISA9, FRRS1L and NRN1. The proteins of the inner and outer core serve as a platform for other, more peripherally associated AMPAR constituents. Alone or in combination, these auxiliary subunits control the gating and pharmacology of the AMPAR complex and profoundly impact their biogenesis and protein processing. Expressed in the brain (at protein level).