GRIA1 and schizophrenia: GluA1 subunits, which are most often assembled into GluA1/2 tetrameric receptors, demonstrate altered subcellular distribution along the forward trafficking pathway, supporting the interpretation that some AMPA receptor subpopulations may be exported from the ER more rapidly in schizophrenia.50 Although AMPA subunit expression in the ER compartment is reported to be intact in schizophrenia,51 the glycosylation state of AMPA subunits was not specifically assessed.