Towards understanding the phosphorylation code of tau

2012 ◽  
Vol 40 (4) ◽  
pp. 698-703 ◽  
Author(s):  
Guy Lippens ◽  
Laziza Amniai ◽  
Jean-Michel Wieruszeski ◽  
Alain Sillen ◽  
Arnaud Leroy ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Tau Protein ◽  
Enzymatic Reactions ◽  
Qualitative And Quantitative ◽  
Functional Assays ◽  
Phosphorylation Pattern

We describe our efforts to combine in vitro enzymatic reactions with recombinant kinases to phosphorylate the neuronal tau protein, and NMR spectroscopy to unravel the resulting phosphorylation pattern in both qualitative and quantitative manners. This approach, followed by functional assays with the same samples, gives access to the complex phosphorylation code of tau. As a result, we propose a novel hypothesis for the link between tau (hyper)phosphorylation and aggregation.

NMR spectroscopy of the neuronal tau protein: normal function and implication in Alzheimer's disease

2010 ◽  
Vol 38 (4) ◽  
pp. 1006-1011 ◽  
Author(s):  
Isabelle Landrieu ◽  
Arnaud Leroy ◽  
Caroline Smet-Nocca ◽  
Isabelle Huvent ◽  
Laziza Amniai ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Current Knowledge ◽  
Normal Function ◽  
Phosphorylated Tau ◽  
Functional Assays ◽  
Protein Partners ◽  
Proteomics Tool ◽  
Functional Consequences ◽  
Dependent Protein

NMR spectroscopy was used to explore the different aspects of the normal and pathological functions of tau, but proved challenging because the protein contains 441 amino acids and has poor signal dispersion. We have set out to dissect the phosphorylation patterns of tau in order to understand better its role in the aggregation process and microtubule-binding regulation. Our current knowledge on the functional consequences of specific phosphorylations is still limited, mainly because producing and assessing quantitatively phosphorylated tau samples is far from straightforward, even in vitro. We use NMR spectroscopy as a proteomics tool to characterize the phosphorylation patterns of tau, after in vitro phosphorylation by recombinant kinases. The phosphorylated tau can next be use for functional assays or interaction assays with phospho-dependent protein partners, such as the prolyl cis–trans isomerase Pin1.

QUALITATIVE AND QUANTITATIVE PHYTOCHEMICAL SCREENING AND IN VITRO ANTIOXIDANT EVALUATION OF PERGULARIA DAEMIA

2018 ◽  
Vol 24 (2) ◽  
Author(s):  
GITA MISHRA ◽  
HEMESHWER KUMAR CHANDRA ◽  
NISHA SAHU ◽  
SATENDRA KUMAR NIRALA ◽  
MONIKA BHADAURIA
Keyword(s):  
Reducing Sugars ◽  
Antioxidant Properties ◽  
Phytochemical Analysis ◽  
Phytochemical Screening ◽  
Qualitative And Quantitative ◽  
The Family ◽  
Ethanolic Extracts ◽  
Antioxidant Evaluation ◽  
In Vitro Antioxidant Activity

Pergularia daemia belongs to the family Asclepiadaceae, known to have anticancer, anti-inflammatory activity. Aim of the present study was to evaluate qualitative and quantitative phytochemical and antioxidant properties of ethanolic extracts of leaf, stem and root parts of P. daemia . Preliminary phytochemical analysis and in vitro antioxidant properties were evaluated by standard methods. The qualitative phytochemical analysis of P. daemia showed presence of flavonoids, tannins, alkaloid, phytosterol, carbohydrate, phenol, saponin, glycosides, terpenoids, steroids proteins and reducing sugars. Quantitative analysis showed polyphenol, flavonoid, flavonone, flavone and flavonol in P. daemia leaves, stem and root in considerable quantity. The in vitro antioxidant activity of P. daemia clearly demonstrated that leaf, stem and root parts have prominent antioxidant properties and was effective in scavenging free radicals.

The Comparative Study of Equisetum pratense, E. sylvaticum, E. telmateia: Accumulation of Silicon, Antioxidant and Antimicrobial Screening

2019 ◽  
Vol 70 (7) ◽  
pp. 2519-2523
Author(s):  
Denisa Batir Marin ◽  
Oana Cioanca ◽  
Mihai Apostu ◽  
Cristina Gabriela Tuchilus ◽  
Cornelia Mircea ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Methanol Extract ◽  
Previous Treatment ◽  
Total Phenolic ◽  
Quantitative Chemical Analysis ◽  
Qualitative And Quantitative ◽  
Antioxidant And Antimicrobial Activity ◽  
The Comparative Study

The objective of the current study is represented by the determination of silica and a phytochemical screening of phenolic derivates of some Equisetum species. The antioxidant and antimicrobial activity for Equisetum pratense Ehrh.,, Equisetum sylvaticum L. and Equisetum telmateia Ehrh. (sin. Equisetum maximum Lam.) were also investigated. The concentration of silicon (Si) in plants was determined by the spectrophotometric method using previous treatment with NaOH 50% both for the stem and the nodal branches [1]. Results obtained varied from 95.12 to 162.10 SiO2 mg/g dry plant which represents 4.44% to 7.58% Si/100g dry sample. Two types of total extracts were obtained using different solvents and were subjected to qualitative and quantitative chemical analysis considering total phenolic content [2]. The highest concentration of investigated compounds was found in the methanolic extract, E. sylvaticum, 196.5mg/g dry sample. Antioxidant activity was monitored spectrophotometrically and expressed in terms of IC50 (�g/mL) [3]. Values gathered ranged from 261.7 to 429.5 �g/mL. The highest capacity to neutralized DPPH radicals was found in E. sylvaticum. In vitro antimicrobial activity was determined using difusimetric method [4]. Testing was performed on four microorganisms: three strains of bacteria and one species of fungi. Different effects were noticed against the bacteria, furthermore the methanol extract appeared to be most efficient. All extracts showed significand antimicrobial activity against Staphylococcus aureus (ATCC 25923) and Candida albicans (ATCC 90028) and weak to no activity against Pseudomonas aeruginosa (ATCC 27853) and Escherichia coli (ATCC 25922).

Targeting Tau Hyperphosphorylation via Kinase Inhibition: Strategy to Address Alzheimer's Disease

2020 ◽  
Vol 20 (12) ◽  
pp. 1059-1073 ◽  
Author(s):  
Ahmad Abu Turab Naqvi ◽  
Gulam Mustafa Hasan ◽  
Md. Imtaiyaz Hassan
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Tau Protein ◽  
Glycogen Synthase ◽  
Paired Helical Filaments ◽  
Tau Hyperphosphorylation ◽  
Microtubule Stabilization ◽  
Extracellular Signal

Microtubule-associated protein tau is involved in the tubulin binding leading to microtubule stabilization in neuronal cells which is essential for stabilization of neuron cytoskeleton. The regulation of tau activity is accommodated by several kinases which phosphorylate tau protein on specific sites. In pathological conditions, abnormal activity of tau kinases such as glycogen synthase kinase-3 β (GSK3β), cyclin-dependent kinase 5 (CDK5), c-Jun N-terminal kinases (JNKs), extracellular signal-regulated kinase 1 and 2 (ERK1/2) and microtubule affinity regulating kinase (MARK) lead to tau hyperphosphorylation. Hyperphosphorylation of tau protein leads to aggregation of tau into paired helical filaments like structures which are major constituents of neurofibrillary tangles, a hallmark of Alzheimer’s disease. In this review, we discuss various tau protein kinases and their association with tau hyperphosphorylation. We also discuss various strategies and the advancements made in the area of Alzheimer's disease drug development by designing effective and specific inhibitors for such kinases using traditional in vitro/in vivo methods and state of the art in silico techniques.

scholarly journals Assessment of Photo-Induced Cytotoxic Activity of Cachrys sicula and Cachrys libanotis Enriched-Coumarin Extracts against Human Melanoma Cells

Plants ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 123
Author(s):  
Mariangela Marrelli ◽  
Maria Rosaria Perri ◽  
Valentina Amodeo ◽  
Francesca Giordano ◽  
Giancarlo A. Statti ◽  
...  
Keyword(s):  
Phenolic Content ◽  
Melanoma Cells ◽  
Therapeutic Approaches ◽  
Qualitative And Quantitative ◽  
Aerial Parts ◽  
Naturally Occurring ◽  
Quantitative Analyses ◽  
Solid Liquid ◽  
Uva Radiation

Photochemotherapy is one of the most interesting current therapeutic approaches for the treatment of melanoma. Different classes of naturally occurring phytochemicals demonstrated interesting photoactive properties. The aim of this study was to evaluate the photocytotoxic potential of two Cachrys species from Southern Italy: C. sicula and C. libanotis (Apiaceae). The enriched-coumarin extracts were obtained from aerial parts through both traditional maceration and pressurized cyclic solid-liquid (PCSL) extraction using Naviglio extractor®. Qualitative and quantitative analyses of furanocoumarins were performed with GC-MS. The photocytotoxic effects were verified on C32 melanoma cells irradiated at a dose of 1.08 J/cm2. The apoptotic responses were also assessed. Moreover, phenolic content and the in vitro antioxidant potential were estimated. Xanthotoxin, bergapten, and isopimpinellin were identified. All the samples induced concentration-dependent photocytotoxic effects (IC50 ranging from 3.16 to 18.18 μg/mL). The C. libanotis sample obtained with Naviglio extractor® was the most effective one (IC50 = 3.16 ± 0.21 μg/mL), followed by C. sicula sample obtained with the same technique (IC50 = 8.83 ± 0.20 μg/mL). Both Cachrys samples obtained through PCSL induced up-regulation of apoptotic signals such as BAX (Bcl2-associated X protein) and PARP (poly ADP-ribose polymerase) cleavage. Moreover, these samples proved to be more photoactive, giving a greater upregulation of p21 protein in the presence of UVA radiation. Obtained results suggest that investigated species could be promising candidates for further investigations aimed to find new potential drugs for the photochemotherapy of skin cancer.

scholarly journals Evaluation of the Expression of CCR5 and CX3CR1 Receptors and Correlation with the Functionality of T Cells in Women infected with ZIKV during Pregnancy

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 191
Author(s):  
Débora Familiar-Macedo ◽  
Iury Amancio Paiva ◽  
Jessica Badolato-Corrêa da Silva ◽  
Fabiana Rabe de Carvalho ◽  
Helver Gonçalves Dias ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
Clinical Outcome ◽  
Cell Responses ◽  
Functional Assays ◽  
Asymptomatic Children ◽  
Cd107a Expression ◽  
Congenital Zika Syndrome ◽  
Ifn Γ

There have been reports of neurological abnormalities associated with the Zika virus (ZIKV), such as congenital Zika syndrome (CZS) in children born to mothers infected during pregnancy. We investigated how the immune response to ZIKV during pregnancy is primed and conduct a thorough evaluation of the inflammatory and cytotoxic profiles as well as the expression of CCR5 and CX3CR1. We compared the reactivity of T cells to ZIKV peptides in convalescent mothers infected during pregnancy. The child’s clinical outcome (i.e., born with or without CZS) was taken to be the variable. The cells were stimulated in vitro with ZIKV peptides and evaluated using the ELISPOT and flow cytometry assays. After in vitro stimulation with ZIKV peptides, we observed a tendency toward a higher Interferon gamma (IFN-γ)-producing T cell responses in mothers who had asymptomatic children and a higher CD107a expression in T cells in mothers who had children with CZS. We found a higher frequency of T cells expressing CD107a+ and co-expressing CX3CR1+CCR5+, which is much clearer in the T cells of mothers who had CZS children. We suggest that this differential profile influenced the clinical outcome of babies. These data need to be further investigated, including the evaluation of other ZIKV peptides and markers and functional assays.

scholarly journals Axotrophin/MARCH7 acts as an E3 ubiquitin ligase and ubiquitinates tau protein in vitro impairing microtubule binding

2014 ◽  
Vol 1842 (9) ◽  
pp. 1527-1538 ◽  
Author(s):  
Katharina Flach ◽  
Ellen Ramminger ◽  
Isabel Hilbrich ◽  
Annika Arsalan-Werner ◽  
Franziska Albrecht ◽  
...  
Keyword(s):  
Ubiquitin Ligase ◽  
Tau Protein ◽  
E3 Ubiquitin Ligase ◽  
Microtubule Binding

scholarly journals A Novel Human Ada2 Homologue Functions with Gcn5 or Brg1 To Coactivate Transcription

2003 ◽  
Vol 23 (19) ◽  
pp. 6944-6957 ◽  
Author(s):  
Nickolai A. Barlev ◽  
Alexander V. Emelyanov ◽  
Paola Castagnino ◽  
Philip Zegerman ◽  
Andrew J. Bannister ◽  
...  
Keyword(s):  
Histone Acetylation ◽  
Chromatin Remodeling ◽  
Adaptor Protein ◽  
Saga Complex ◽  
Yeast Two Hybrid ◽  
Functional Assays ◽  
Two Hybrid ◽  
Histone Acetyltransferase Activity

ABSTRACT In yeast, the transcriptional adaptor yeast Ada2 (yAda2) is a part of the multicomponent SAGA complex, which possesses histone acetyltransferase activity through action of the yGcn5 catalytic enzyme. yAda2, among several SAGA proteins, serves to recruit SAGA to genes via interactions with promoter-bound transcription factors. Here we report identification of a new human Ada2 homologue, hAda2β. Ada2β differs both biochemically and functionally from the previously characterized hAda2α, which is a stable component of the human PCAF (human Gcn5 homologue) acetylase complex. Ada2β, relative to Ada2α, interacted selectively, although not stably, with the Gcn5-containing histone acetylation complex TFTC/STAGA. In addition, Ada2β interacted with Baf57 (a component of the human Swi/Snf complex) in a yeast two-hybrid screen and associated with human Swi/Snf in vitro. In functional assays, hAda2β (but not Ada2α), working in concert with Gcn5 (but not PCAF) or Brg1 (the catalytic component of hSwi/Snf complex), increased transcription via the B-cell-specific transcription factor Pax5/BSAP. These findings support the view that Gcn5 and PCAF have distinct roles in vivo and suggest a new mechanism of coactivator function, in which a single adaptor protein (Ada2β) can coordinate targeting of both histone acetylation and chromatin remodeling activities.

scholarly journals Trichilones A–E: New Limonoids from Trichilia adolfi

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3070
Author(s):  
Mariela Gonzalez-Ramirez ◽  
Ivan Limachi ◽  
Sophie Manner ◽  
Juan C. Ticona ◽  
Efrain Salamanca ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
High Field ◽  
Chemical Constituents ◽  
Ethanol Extract ◽  
Raw 264.7 Cells ◽  
Raw 264.7 ◽  
Murine Macrophage ◽  
New Metabolites

In addition to the trichilianones A–D recently reported from Trichilia adolfi, a continuing investigation of the chemical constituents of the ethanol extract of the bark of this medicinal plant yielded the five new limonoids 1–5. They are characterized by having four fused rings and are new examples of prieurianin-type limonoids, having a ε-lactone which in 4 and 5 is α, β- unsaturated. The structures of the isolated metabolites were determined by high field NMR spectroscopy and HR mass spectrometry. The new metabolites were shown to have the ε-lactone fused with a tetrahydrofuran ring which is connected to an oxidized hexane ring joined with a cyclo-pentanone having a 3-furanyl substituent. As the crude extract possesses antileishmanial activity, the compounds were assayed for cytotoxic and antiparasitic activities in vitro in murine macrophage cells (raw 264.7 cells) and in Leishmania amazoniensis as well as L. braziliensis promastigotes. Metabolites 1–3 and 5 showed moderate cytotoxicity (between 30–94 µg/mL) but are not responsible for the antileishmanial effect of the extract.

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