Abstract
In some neurodegenerative disorders, tau protein accumulates in astrocytes and/or oligodendrocytes, even though these glial cells produce much less of the protein than do neurons. Testing the hypothesis that the aggregated tau in glia derives from neurons, Narasimhan et al. (https://doi.org/10.1084/jem.20190783) make the unexpected discovery that neuronal tau expression is not required for the formation of glial tau inclusions. The circumstances governing the variable cell-specificity of tauopathy thus remain to be fully defined.