Is tau a suitable therapeutical target in tauopathies?

Tau is an intracellular protein, found mainly in neurons, but it can also be found in the extracellular space in pathological situations. Here we discuss whether intracellular tau, in aggregated form or modified by phosphorylation, could be toxic inside a neuron. On the other hand, it has been proposed that extracellular tau could be toxic. In this review, we address the question if the elimination of tau would be a possible therapeutic method to avoid tauopathy disorder and we suggest ways to eliminate intracellular and extracellular tau as treatment.