Neuronal nuclear tau and neurodegeneration

•Tau is present in the nucleus.•Tau binds to DNA present in the nucleolus and pericentromeric heterochromatin.•Tau bind to RNA.•Pathogenic tau alters nuclear transport.•Nuclear tau increases during aging and neurodegeneration. Tau is a well-known microtubule-associated protein related to its cytoplasmic localization in a neuronal cell. However, tau has been located at the cell nucleus where it could be a nucleic acid-associated protein by its preferential binding to DNA sequences present in the nucleolus and pericentromeric heterochromatin. This less well-known localization of tau could not be trivial, since during aging, an increase in the amount of nuclear tau takes place and it may be related to the described role of tau in the activation of transposons and further aging acceleration.