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-Synuclein contributes to GSK-3β-catalyzed Tau phosphorylation in Parkinsons disease models
* Department of Biochemistry, Molecular and Cellular Biology, Georgetown University, Washington, District of Columbia, USA; and
Department of Research, Maricopa Integrated Health System, Phoenix, Arizona, USA
1 Correspondence: Laboratory of Molecular Neurochemistry, The Research Bldg., Rm. W222, 3970 Reservoir Rd., NW, Washington, D.C. 20007, USA. E-mail: sidhua{at}georgetown.edu
We have shown in the parkinsonism-inducing neurotoxin MPP+/MPTP model that
-Synuclein (
-Syn), a presynaptic protein causal in Parkinsons disease (PD), contributes to hyperphosphorylation of Tau (p-Tau), a protein normally linked to tauopathies, such as Alzheimers disease (AD). Here, we investigated the kinase involved and show that the Tau-specific kinase, glycogen synthase kinase 3β (GSK-3β), is robustly activated in various MPP+/MPTP models of Parkinsonism (SH-SY5Y cotransfected cells, mesencephalic neurons, transgenic mice overexpressing
-Syn, and postmortem striatum of PD patients). The activation of GSK-3β was absolutely dependent on the presence of
-Syn, as indexed by the absence of p-GSK-3β in cells lacking
-Syn and in
-Syn KO mice. MPP+ treatment induced translocation and accumulation of p-GSK-3β in nuclei of SH-SY5Y cells and mesencephalic neurons. Through coimmunoprecipitation (co-IP), we found that
-Syn, pSer396/404-Tau, and p-GSK-3β exist as a heterotrimeric complex in SH-SY5Y cells. GSK-3β inhibitors (lithium and TDZD-8) protected against MPP+-induced events in SH-SY5Y cells, preventing cell death and p-GSK-3β formation, by reversing increases in
-Syn accumulation and p-Tau formation. These data unveil a previously unappreciated role of
-Syn in the induction of p-GSK-3β, and demonstrate the importance of this kinase in the genesis and maintenance of neurodegenerative changes associated with PD.—Duka, T., Duka, V., Joyce, J. N., Sidhu, A.
-Synuclein contributes to GSK-3β-catalyzed Tau phosphorylation in Parkinsons disease models.
Key Words: synucleopathies tauopathies neurodegeneration Alzheimers disease
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