Inducible Expression of Tau Repeat Domain in Cell Models of Tauopathy

Inna Khlistunova, Jacek Biernat, Yipeng Wang, Marcus Pickhardt, Martin von Bergen, Zuzana Gazova, Eckhard Mandelkow, Eva-Maria Mandelkow
2005 Journal of Biological Chemistry  
We generated several cell models of tauopathy in order to study the mechanisms of neurodegeneration in diseases involving abnormal changes of tau protein. N2a neuroblastoma cell lines were created that inducibly express different variants of the repeat domain of tau (tau RD ) when exposed to doxycycline (Tet-On system). The following three constructs were chosen: (i) the repeat domain of tau that coincides with the core of Alzheimer paired helical filaments; (ii) the repeat domain with the
more » ... ion mutation ⌬K280 known from frontotemporal dementia and highly prone to spontaneous aggregation; and (iii) the repeat domain with ⌬K280 and two proline point mutations that inhibit aggregation. The comparison of wild-type, pro-aggregation, and anti-aggregation mutants shows the following. (a) Aggregation of tau RD is toxic to cells. (b) The degree of aggregation and toxicity depends on the propensity for ␤-structure. (c) Soluble mutants of tau RD that cannot aggregate are not toxic. (d) Aggregation is preceded by fragmentation. (e) Fragmentation of tau RD in cells is initially due to a thrombin-like protease activity. (f) Phosphorylation of tau RD (at KXGS motifs) precedes aggregation but is not correlated with the degree of aggregation. (g) Aggregates of tau RD disappear when the expression is silenced, showing that aggregation is reversible. (h) Aggregation can be prevented by drugs and even pre-formed aggregates can be dissolved again by drugs. Thus, the cell models open up new insights into the relationship between the structure, expression, phosphorylation, aggregation, and toxicity of tau RD that can be used to test current hypotheses on tauopathy and to develop drugs that prevent the aggregation and degeneration of cells.
doi:10.1074/jbc.m507753200 pmid:16246844 fatcat:tutxd5gdwvcenfeusyp56d2say