Pseudophosphorylation of tau protein alters its ability for self-aggregation: Pseudo-phosphorylated tau aggregation (original) (raw)
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Identification of the Tau phosphorylation pattern that drives its aggregation
Proceedings of the National Academy of Sciences
Determining the functional relationship between Tau phosphorylation and aggregation has proven a challenge owing to the multiple potential phosphorylation sites and their clustering in the Tau sequence. We use here in vitro kinase assays combined with NMR spectroscopy as an analytical tool to generate well-characterized phosphorylated Tau samples and show that the combined phosphorylation at the Ser202/Thr205/Ser208 sites, together with absence of phosphorylation at the Ser262 site, yields a Tau sample that readily forms fibers, as observed by thioflavin T fluorescence and electron microscopy. On the basis of conformational analysis of synthetic phosphorylated peptides, we show that aggregation of the samples correlates with destabilization of the turn-like structure defined by phosphorylation of Ser202/Thr205.
In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein
Journal of Visualized Experiments, 2015
Alzheimer's disease is one of a large group of neurodegenerative disorders known as tauopathies that are manifested by the neuronal deposits of hyperphosphorylated tau protein in the form of neurofibrillary tangles (NFTs). The density of NFT correlates well with cognitive impairment and other neurodegenerative symptoms, thus prompting the endeavor of developing tau aggregation-based therapeutics. Thus far, however, tau aggregation assays use recombinant or synthetic tau that is devoid of the pathology-related phosphorylation marks. Here we describe two assays using recombinant, hyperphosphorylated tau as the subject. These assays can be scaled up for high-throughput screens for compounds that can modulate the kinetics or stability of hyperphosphorylated tau aggregates. Novel therapeutics for Alzheimer's disease and other tauopathies can potentially be discovered using hyperphosphorylated tau isoforms.
Hyperphosphorylation-induced self assembly of murine tau: a comparison with human tau
Journal of Neural Transmission, 2005
Alzheimer's disease-like neurofibrillary pathology is neither seen in rodents nor in transgenic animals expressing the disease causing mutant human APP or mutant human presenilins. Whether the absence of this pathology is due to inability of the murine tau to self assemble into filaments or due to some other factors is not understood. In this study, we compared recombinant murine and human taus in their ability to form filaments by AD-like hyperphosphorylation in vitro. Human and murine taus, 0N4R, were generated as recombinant proteins and phosphorylated with rat brain extract as a source of protein kinases. We found that murine tau could be hyperphosphorylated to similar stoichiometry and manner as human tau. Upon hyperphosphorylation, murine tau was able to self polymerize into bundles of paired helical filament-and straight filament-like morphology. The filaments obtained from self assembly of murine tau closely resembled those formed from identically treated human tau. Moreover, like human tau, 60-70% of murine tau aggregated on hyperphosphorylation.
Mechanisms of Tau Self-Aggregation and Neurotoxicity
Current Alzheimer Research, 2011
Pathological tau protein aggregates can be found in brain of patients with some of the neurodegenerative diseases collectively known as tauopathies, which include Alzheimer's disease (AD). Since tau post-translational modifications including phosphorylations, glycosylations, truncation and the subsequent aggregation in oligomers, paired helical filaments (PHFs) and neurofibrillary tangles (NFTs), correlate with cognitive impairment and neurodegeneration in AD, a pathogenic role for tau and its modifications has been raised. Here we summarize the current status of knowledge about tau modifications under pathologic conditions and the evidence supporting neurotoxic-or neuroprotective-roles of the diverse forms of modified and aggregated tau. Finally, we analyze the structural and functional tau alterations found in different tauopathies and how these modifications are related to the pathophysiologic mechanisms of neurodegeneration.
Journal of Biological Chemistry, 2006
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 deletion 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.
Tau Phosphorylation and Aggregation as a Therapeutic Target in Tauopathies
CNS & Neurological Disorders - Drug Targets, 2010
Tauopathies are neurodegenerative diseases characterized by insoluble hyperphosphorylated deposits of the microtubuleassociated protein tau in the central nervous system. In these disorders, tau is believed to cause neurodegeneration and neuronal loss due to the loss of function of the normal protein, and/or the gain of toxic properties by generating multimeric species. The obstacles found in amyloid-based therapies in Alzheimer's disease, the most common tauopathy, have stimulated the search for alternative targets, including tau. In this article, we review the strategies aimed at reducing tau phosphorylation and aggregation as a target for drug intervention in tauopathies.
Biomolecules, 2016
Abnormal deposition of misprocessed and aggregated proteins is a common final pathway of most neurodegenerative diseases, including Alzheimer's disease (AD). AD is characterized by the extraneuronal deposition of the amyloid β (Aβ) protein in the form of plaques and the intraneuronal aggregation of the microtubule-associated protein tau in the form of filaments. Based on the biochemically diverse range of pathological tau proteins, a number of approaches have been proposed to develop new potential therapeutics. Here we discuss some of the most promising ones: inhibition of tau phosphorylation, proteolysis and aggregation, promotion of intra-and extracellular tau clearance, and stabilization of microtubules. We also emphasize the need to achieve a full understanding of the biological roles and post-translational modifications of normal tau, as well as the molecular events responsible for selective neuronal vulnerability to tau pathology and its propagation. It is concluded that answering key questions on the relationship between Aβ and tau pathology should lead to a better understanding of the nature of secondary tauopathies, especially AD, and open new therapeutic targets and strategies.
P3-254 Hyperphosphorylation induced self-assembly of murine tau: a comparison with human tau
Neurobiology of Aging, 2004
Alzheimer's disease-like neurofibrillary pathology is neither seen in rodents nor in transgenic animals expressing the disease causing mutant human APP or mutant human presenilins. Whether the absence of this pathology is due to inability of the murine tau to self assemble into filaments or due to some other factors is not understood. In this study, we compared recombinant murine and human taus in their ability to form filaments by AD-like hyperphosphorylation in vitro. Human and murine taus, 0N4R, were generated as recombinant proteins and phosphorylated with rat brain extract as a source of protein kinases. We found that murine tau could be hyperphosphorylated to similar stoichiometry and manner as human tau. Upon hyperphosphorylation, murine tau was able to self polymerize into bundles of paired helical filament-and straight filament-like morphology. The filaments obtained from self assembly of murine tau closely resembled those formed from identically treated human tau. Moreover, like human tau, 60-70% of murine tau aggregated on hyperphosphorylation.