MAPT and Alzheimer disease: In particular, the consistent nucleolar localisation of these phosphoepitopes observed both in neuroblastoma cells under different conditions (proliferative, differentiated, and transcriptionally inhibited) and in hippocampal CA1 neurons across ageing and Alzheimer’s disease stages points to a potential role of phosphorylated tau in supporting nucleolar structure and function, possibly contributing to the maintenance of ribosomal biogenesis and transcriptional homeostasis.