NMR-basierte Charakterisierung phosphorylierungsinduzierter, konformationeller Übergänge in dem Alzheimer-assozierten Protein Tau
Zusammenfassung der Projektergebnisse
The Tau protein, which is a microtubule-associated intrinsically disordered protein, plays a central role in the progression of Alzheimer disease. In Alzheimer disease, Tau becomes excessively phosphorylated, loses its ability to bind to microtubuli, and aggregates into intracellular abnormal protein deposits. Considerable effort has been made over the years to investigate the impact of phosphorylation on the structure of Tau as a means to understand its function and mechanisms of action, but these efforts have primarily used traditional biochemistry approaches and therefore have addressed structure and function at a relatively primitive level. Using a combination of NMR spectroscopy, molecular biology and computational chemistry we studied the structural and dynamic changes induced by phosphorylation of Tau. We showed that pseudophosphorylation causes an opening of the transient folding of Tau, suggesting - together with previous studies on the Parkinson-related protein α-synuclein - that networks of transient long-range interactions are common properties of intrinsically disordered proteins and that their modulation is important for aggregation. We also identified enhanced polyproline II sampling in aggregation-nucleation sites of Tau, supporting suggestions that this region of conformational space is important for pathogenic aggregation. We further demonstrated that the microtubule-associated protein/microtubule affinity-regulating kinase MARK2 binds to the N-terminal tail of Tau and selectively phosphorylates three major and five minor serine residues in the repeat domain and C-terminal tail. Structural changes induced by MARK2 mediated phosphorylation of Tau were highly localized in the proximity of the phosphorylation site and did not affect the global conformation, in contrast to phosphorylation in the prolinerich region. Furthermore, single-residue analysis of binding of Tau to microtubules provided support for a model in which Tau's hot spots of microtubule interaction bind independently of each other and are differentially affected by phosphorylation.
Projektbezogene Publikationen (Auswahl)
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(2011) Structural impact of proline-directed pseudophosphorylation at AT8, AT100, and PHF1 epitopes on 441-residue tau. J Am Chem Soc 133: 15842-15845
Bibow S, Ozenne V, Biernat J, Blackledge M, Mandelkow E, Zweckstetter M
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(2012) Mapping the potential energy landscape of intrinsically disordered proteins at amino acid resolution. J Am Chem Soc 134: 15138-15148
Ozenne V, Schneider R, Yao M, Huang JR, Salmon L, Zweckstetter M, Jensen MR, Blackledge M
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(2013) Phosphorylation of human Tau protein by microtubule affinity-regulating kinase 2. Biochemistry 52: 9068-9079
Schwalbe M, Biernat J, Bibow S, Ozenne V, Jensen MR, Kadavath H, Blackledge M, Mandelkow E, Zweckstetter M
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(2014) Exploring Free-Energy Landscapes of Intrinsically Disordered Proteins at Atomic Resolution Using NMR Spectroscopy. Chemical reviews : Epub April 11
Jensen MR, Zweckstetter M, Huang JR, Blackledge M
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(2014) Predictive atomic resolution descriptions of intrinsically disordered hTau40 and alpha-synuclein in solution from NMR and small angle scattering. Structure 22: 238-249
Schwalbe M, Ozenne V, Bibow S, Jaremko M, Jaremko L, Gajda M, Jensen MR, Biernat J, Becker S, Mandelkow E, Zweckstetter M, Blackledge M
