In Knock-in mice expressing AP-tagged GluA2 subunits, the presence of an exogenous enzyme—BiRAER, brought by viral infections—allow the biotinylation of GluA2-containing AMPAR, that can be cross-linked in the presence of tetravalent neutravidin added in the extracellular space (Fig. 6a). This evidence concerns the gene GRIA2 and viral infectious disease.