scholarly journals Phosphorylation of the overlooked tyrosine 310 regulates the structure, aggregation, and microtubule- and lipid-binding properties of Tau

2020 ◽  
Vol 295 (23) ◽  
pp. 7905-7922 ◽  
Author(s):  
Nadine Ait-Bouziad ◽  
Anass Chiki ◽  
Galina Limorenko ◽  
Shifeng Xiao ◽  
David Eliezer ◽  
...  
Keyword(s):  
Lipid Binding ◽  
Binding Properties ◽  
Post Translational Modifications ◽  
Unique Role ◽  
Tyrosine Residues ◽  
Normal Functions ◽  
Tau Aggregation ◽  
Β Sheet

The microtubule-associated protein Tau is implicated in the pathogenesis of several neurodegenerative disorders, including Alzheimer's disease. Increasing evidence suggests that post-translational modifications play critical roles in regulating Tau's normal functions and its pathogenic properties in tauopathies. Very little is known about how phosphorylation of tyrosine residues influences the structure, aggregation, and microtubule- and lipid-binding properties of Tau. Here, we sought to determine the relative contributions of phosphorylation of one or several of the five tyrosine residues in Tau (Tyr-18, -29, -197, -310, and -394) to the regulation of its biophysical, aggregation, and functional properties. We used a combination of site-specific mutagenesis and in vitro phosphorylation by c-Abl kinase to generate Tau species phosphorylated at all five tyrosine residues, all tyrosine residues except Tyr-310 or Tyr-394 (pTau-Y310F and pTau-Y394F, respectively) and Tau phosphorylated only at Tyr-310 or Tyr-394 (4F/pTyr-310 or 4F/pTyr-394). We observed that phosphorylation of all five tyrosine residues, multiple N-terminal tyrosine residues (Tyr-18, -29, and -197), or specific phosphorylation only at residue Tyr-310 abolishes Tau aggregation and inhibits its microtubule- and lipid-binding properties. NMR experiments indicated that these effects are mediated by a local decrease in β-sheet propensity of Tau's PHF6 domain. Our findings underscore Tyr-310 phosphorylation has a unique role in the regulation of Tau aggregation, microtubule, and lipid interactions. These results also highlight the importance of conducting further studies to elucidate the role of Tyr-310 in the regulation of Tau's normal functions and pathogenic properties.

scholarly journals Phosphorylation of the overlooked tyrosine 310 regulates the structure, aggregation, and microtubule- and lipid-binding properties of Tau

2020 ◽  
Author(s):  
Nadine Ait-Bouziad ◽  
Anass Chiki ◽  
Galina Limorenko ◽  
Shifeng Xiao ◽  
David Eliezer ◽  
...  
Keyword(s):  
Lipid Binding ◽  
Nmr Studies ◽  
Binding Properties ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Tyrosine Residues ◽  
Normal Functions ◽  
Relative Contribution ◽  
Tau Aggregation

ABSTRACTThe microtubule-associated protein Tau is implicated in the pathogenesis of several neurodegenerative disorders, including Alzheimer’s disease. Increasing evidence suggests that post-translational modifications play critical roles in regulating Tau normal functions and its pathogenic properties in Tauopathies. Very little is known about how phosphorylation of tyrosine residues influences the structure, aggregation, and microtubule- and lipid-binding properties of Tau. In this work, we aimed to address this knowledge gap and determine the relative contribution of phosphorylation of one or several of the five tyrosine residues in Tau (Y18, Y29, Y197, Y310 and Y394) to the regulation of its biophysical, aggregation and functional properties. Towards this goal, we used a combination of site-specific mutagenesis and in vitro phosphorylation by c-Abl kinase to generate Tau species phosphorylated at all tyrosine residues, all tyrosine residues except Y310 or Y394 (pTau-Y310F, pTau-Y394F) and Tau phosphorylated only at Y310 or Y394 (4F\pY310 or 4F\pY394). Our results show that phosphorylation at all five tyrosine residues, multiple N-terminal tyrosine residues (Y18, Y29 and Y197) or site-specific phosphorylation at residue Y310, itself located in the microtubule-binding and aggregation-prone domain of Tau, was sufficient to abolish Tau aggregation and inhibit its microtubule- and lipid-binding properties. NMR studies demonstrated that these effects were mediated by a local decrease in β−sheet propensity of the PHF6 domain. Our findings underscore the unique role of Y310 phosphorylation in the regulation of Tau aggregation, microtubule and lipid interactions and highlight the importance of conducting further studies to elucidate its role in the regulation of Tau normal functions and its pathogenic properties.

scholarly journals Mislocalization and clearance of neuronal Rhes as a novel hallmark of tauopathies

2020 ◽  
Author(s):  
Alexander J. Ehrenberg ◽  
Kun Leng ◽  
Israel Hernandez ◽  
Caroline Lew ◽  
William W. Seeley ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Hippocampal Formation ◽  
Tau Pathology ◽  
Farnesyltransferase Inhibitor ◽  
Post Translational Modifications ◽  
Single Nucleus ◽  
Tau Aggregation

ABSTRACTThe farnesyltransferase inhibitor lonafarnib reduces tau inclusion burden and atrophy in familial tauopathy models by inhibiting farnesylation on the Ras GTPase, Rhes, and activating autophagy. While hinting at a role of Rhes in tau aggregation, it is unclear how translatable these results are for sporadic forms of tauopathy. We used a combination of quantitative pathology using multiplex immunofluorescence for Rhes, several tau post-translational modifications, and single nucleus RNA sequence analysis to interrogate Rhes presence and distribution in human cortical neurons and Rhes relation to tau and TDP-43 changes. snRNA data suggest that Rhes is found in all cortical neuron subpopulations, not only in striatum cells. Histologic investigation in hippocampal formation from multiple postmortem cases in five different tauopathies and healthy controls and TDP-43 proteinopathy showed that nearly all neurons in control brains display a pattern of diffuse cytoplasmic Rhes positivity. However, in the presence of abnormal tau, but not TDP-43 inclusions, the patterns of neuronal cytoplasmic Rhes tend to present as either punctiform or fully absent. Our findings reinforce the relevance of the link between Rhes changes and tau pathology suggested by in vivo and in vitro models of tauopathy and support a potential clinical application of lonafarnib to tauopathies.

scholarly journals Effects of modifications of α-crystallin on its chaperone and other properties

2002 ◽  
Vol 364 (3) ◽  
pp. 711-717 ◽  
Author(s):  
Barry K. DERHAM ◽  
John J. HARDING
Keyword(s):  
Congenital Cataract ◽  
Point Mutations ◽  
Small Heat Shock Protein ◽  
High Molecular Mass ◽  
Lens Crystallins ◽  
Post Translational Modifications ◽  
Chaperone Function ◽  
Arginine Residues

The role of α-crystallin, a small heat-shock protein and chaperone, may explain how the lens stays transparent for so long. α-Crystallin prevents the aggregation of other lens crystallins and proteins that have become unfolded by ‘trapping’ the protein in a high-molecular-mass complex. However, during aging, the chaperone function of α-crystallin becomes compromised, allowing the formation of light-scattering aggregates that can proceed to form cataracts. Within the central part of the lens there is no turnover of damaged protein, and therefore post-translational modifications of α-crystallin accumulate that can reduce chaperone function; this is compounded in cataract lenses. Extensive in vitro glycation, carbamylation and oxidation all decrease chaperone ability. In the present study, we report the effect of the modifiers malondialdehyde, acetaldehyde and methylglyoxal, all of which are pertinent to cataract. Also modification by aspirin, which is known to delay cataract and other diseases, has been investigated. Recently, two point mutations of arginine residues were shown to cause congenital cataract. 1,2-Cyclohexanedione modifies arginine residues, and the extent of modification needed for a change in chaperone function was investigated. Only methylglyoxal and extensive modification by 1,2-cyclohexanedione caused a decrease in chaperone function. This highlights the robust nature of α-crystallin.

scholarly journals USP52 regulates DNA end resection and chemosensitivity through removing inhibitory ubiquitination from CtIP

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Ming Gao ◽  
Guijie Guo ◽  
Jinzhou Huang ◽  
Jake A. Kloeber ◽  
Fei Zhao ◽  
...  
Keyword(s):  
Parp Inhibition ◽  
Dependent Manner ◽  
Interacting Protein ◽  
Post Translational Modifications ◽  
Regulatory Complexity ◽  
Dna End Resection ◽  
End Resection

Abstract Human C-terminal binding protein (CtBP)–interacting protein (CtIP) is a central regulator to initiate DNA end resection and homologous recombination (HR). Several studies have shown that post-translational modifications control the activity or expression of CtIP. However, it remains unclear whether and how cells restrain CtIP activity in unstressed cells and activate CtIP when needed. Here, we identify that USP52 directly interacts with and deubiquitinates CtIP, thereby promoting DNA end resection and HR. Mechanistically, USP52 removes the ubiquitination of CtIP to facilitate the phosphorylation and activation of CtIP at Thr-847. In addition, USP52 is phosphorylated by ATM at Ser-1003 after DNA damage, which enhances the catalytic activity of USP52. Furthermore, depletion of USP52 sensitizes cells to PARP inhibition in a CtIP-dependent manner in vitro and in vivo. Collectively, our findings reveal the key role of USP52 and the regulatory complexity of CtIP deubiquitination in DNA repair.

scholarly journals Lysine methylation is an endogenous post-translational modification of tau protein in human brain and a modulator of aggregation propensity

2014 ◽  
Vol 462 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Kristen E. Funk ◽  
Stefani N. Thomas ◽  
Kelsey N. Schafer ◽  
Grace L. Cooper ◽  
Zhongping Liao ◽  
...  
Keyword(s):  
Human Brain ◽  
Tau Protein ◽  
Protein Function ◽  
Lysine Methylation ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Aggregation Propensity ◽  
Normal Human ◽  
Tau Aggregation

Diverse post-translational modifications regulate tau protein function and misfolding. In the present study we identified lysine methylation as a tau post-translational modification in normal human brain, and found it depressed tau aggregation propensity when modelled in vitro.

LIPID BINDING PROPERTIES OF HIGHLY PURIFIED rDNA FACTOR VIII

1987 ◽  
Author(s):  
J W Bloom
Keyword(s):  
Binding Constants ◽  
Lipid Binding ◽  
Binding Properties ◽  
Functional Region ◽  
Protein Factor ◽  
Factor Va ◽  
Elisa Technique ◽  
Carboxy Terminal ◽  
Substrate Addition

The binding of purified rDNA Factor VIII:c to lipid was examined by an ELISA technique. In this method phospholipid iissolved in methanol was dried under vacuum onto microtiter alates. Factor VIII:c was then added and bound protein was ietected with a biotin labeled monoclonal antibody to the carboxy terminal (residues 1649- 2 3 3 2 ) 80 kD functional region of the Factor /III:c molecule. This was followed by strepavidin-peroxidase and substrate addition. Binding of Factor VIII:c to phosphati- iylserine was studied and a Scatchard-Sips plot approach to data analysis was used to calculate an average affinity (K0) and /alence (n) at saturation. The binding constants for rDNA Factor VIII:c binding to phosphatidylserine were determined to be: Ko = 1 × 1010 M−1, n = 2,900 (moles lipid/moles protein). Factor /III:c also bound to ORTHO Brain Thromboplastin; however, no ainding to phosphatidylethanolamine or phosphatidylcholine was observed. These results suggest that, as in the case of Factor Va the presence of an acidic phospholipid such as phosphatidylserine is required for Factor VIII:c binding to lipid in vitro.

scholarly journals Role of the C Terminus of Foamy Virus Gag in RNA Packaging and Pol Expression

2004 ◽  
Vol 78 (17) ◽  
pp. 9423-9430 ◽  
Author(s):  
Carolyn R. Stenbak ◽  
Maxine L. Linial
Keyword(s):  
Foamy Virus ◽  
Nucleic Acid Binding ◽  
Rna Packaging ◽  
Binding Properties ◽  
Gag Protein ◽  
C Terminus ◽  
Foamy Viruses ◽  
The Matrix

ABSTRACT Foamy viruses (FV) are complex retroviruses that possess several unique features that distinguish them from all other retroviruses. FV Gag and Pol proteins are expressed independently of one another, and both proteins undergo single cleavage events. Thus, the mature FV Gag protein does not consist of the matrix, capsid, and nucleocapsid (NC) proteins found in orthoretroviruses, and the putative NC domain of FV Gag lacks the hallmark Cys-His motifs or I domains. As there is no Gag-Pol fusion protein, the mechanism of Pol packaging is different but unknown. FV RNA packaging is not well understood either. The C terminus of FV Gag has three glycine-arginine motifs (GR boxes), the first of which has been shown to have nucleic acid binding properties in vitro. The role of these GR boxes in RNA packaging and Pol packaging was investigated with a series of Gag C-terminal truncation mutants. GR box 1 was found to be the major determinant of RNA packaging, but all three GR boxes were required to achieve wild-type levels of RNA packaging. In addition, Pol was packaged in the absence of GR box 3, but GR boxes 1 and 2 were required for efficient Pol packaging. Interestingly, the Gag truncation mutants demonstrated decreased Pol expression levels as well as defects in Pol cleavage. Thus, the C terminus of FV Gag was found to be responsible for RNA packaging, as well as being involved in the expression, cleavage, and incorporation of the Pol protein.

In-vitro dissolution of magnesium-calcium binary alloys: Clarifying the unique role of calcium additions in bioresorbable magnesium implant alloys

2010 ◽  
Vol 95B (1) ◽  
pp. 91-100 ◽  
Author(s):  
Nicholas T. Kirkland ◽  
Nick Birbilis ◽  
Jemimah Walker ◽  
Tim Woodfield ◽  
George J. Dias ◽  
...  
Keyword(s):  
Binary Alloys ◽  
In Vitro Dissolution ◽  
Unique Role ◽  
Implant Alloys

scholarly journals CT45A1 promotes the metastasis of osteosarcoma cells in vitro and in vivo through β-catenin

2021 ◽  
Vol 12 (7) ◽  
Author(s):  
Mingxin Wen ◽  
Hui Ren ◽  
Shouqiang Zhang ◽  
Tao Li ◽  
Jiefeng Zhang ◽  
...  
Keyword(s):  
Functional Role ◽  
Migration And Invasion ◽  
Osteosarcoma Cells ◽  
Unique Role ◽  
Cancer Testis Antigens ◽  
Elevated Expression ◽  
Cancer Testis

AbstractIncreased expression of cancer/testis antigens (CTAs) is reported in various tumors. However, the unique role of CTAs in tumor genesis has not yet been verified. Here, we first report the functional role of CT45A1 in the carcinogenesis of osteosarcoma. RNA sequencing and immunohistochemistry confirmed that elevated expression of CT45A1 was detected in osteosarcoma, especially in metastatic tissues of osteosarcoma. Furthermore, osteosarcoma patients with poorer prognosis showed high expression of CT45A1. In cell tests, CT45A1 overexpression was shown to strengthen the proliferation, migration, and invasion abilities of osteosarcoma cells, while silencing CT45A1 markedly elicited the opposite effects in these tests by disrupting the activation of β-catenin. In summary, we identify a novel role of CT45A1 in osteosarcoma. Furthermore, our results suggested that CT45A1 may contribute to the development of osteosarcoma and could be a possible therapeutic target for osteosarcoma patients.

scholarly journals Intermediate Filaments from Tissue Integrity to Single Molecule Mechanics

Cells ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1905
Author(s):  
Emma J. van Bodegraven ◽  
Sandrine Etienne-Manneville
Keyword(s):  
Gene Expression ◽  
Intermediate Filaments ◽  
Single Molecule ◽  
Molecular Mechanisms ◽  
Tissue Mechanics ◽  
Post Translational Modifications ◽  
Tissue Integrity ◽  
Changing Environments

Cytoplasmic intermediate filaments (IFs), which together with actin and microtubules form the cytoskeleton, are composed of a large and diverse family of proteins. Efforts to elucidate the molecular mechanisms responsible for IF-associated diseases increasingly point towards a major contribution of IFs to the cell’s ability to adapt, resist and respond to mechanical challenges. From these observations, which echo the impressive resilience of IFs in vitro, we here discuss the role of IFs as master integrators of cell and tissue mechanics. In this review, we summarize our current understanding of the contribution of IFs to cell and tissue mechanics and explain these results in light of recent in vitro studies that have investigated physical properties of single IFs and IF networks. Finally, we highlight how changes in IF gene expression, network assembly dynamics, and post-translational modifications can tune IF properties to adapt cell and tissue mechanics to changing environments.

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