JUN and Alzheimer disease: Here, we demonstrated altered c‐Fos O‐GlcNAcylation in AD and revealed that the function of c‐Fos O‐GlcNAcylation is to increase the stability of c‐Fos, stimulating its interaction with c‐Jun and the transcriptional activity followed by an induction of Bim, an apoptotic gene, expression therefore directly promoting cell death in the presence of Aβ.