AMPA receptor subunit, GluA1, and KA receptor subunits, GluK2/3, protein levels in Tg2576 mice: Since synaptic dysfunction and/or loss is highly implicated as an early event in the pathophysiology of AD [24], we investigated total levels of the AMPA and KA receptor subunits, GluA1 and GluK2/3, respectively, in the Tg2576 mice using the same tissue samples monitored for ubiquitination and SUMOylation. Here, GRIA1 is linked to Alzheimer disease.