Hsp90 Maintains the Stability and Function of the Tau Phosphorylating Kinase GSK3β

Abstract: Hyperphosphorylation of tau leading to aggregated tau and tangle formation is acommon pathological feature of tauopathies, including Alzheimer's disease. Abnormalphosphorylation of tau by kinases, in particular GSK3β, has been proposed as a pathogenicmechanism in these diseases. In this study we demonstrate that the heat shock protein 90(Hsp90) maintains the stability and function of the GSK3β. By using both rat primarycortical neurons and COS-7 cells, we show that Hsp90 inhibitors lead to a reduction of theprotein level of GSK3β, and that this effect is associated with both a decrease in tauphosphorylation at putative GSK3β sites and an induction in heat shock protein 70 (Hsp70)levels. We further show that Hsp90 associates with the GSK3β regulating its stability andfunction and preventing its degradation by the proteasome.