scholarly journals Tau K321/K353 pseudoacetylation within KXGS motifs regulates tau–microtubule interactions and inhibits aggregation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yuxing Xia ◽  
Brach M. Bell ◽  
Benoit I. Giasson
Keyword(s):  
Protective Mechanism ◽  
Conformational Structure ◽  
Potential Therapeutic Target ◽  
Double Mutation ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Tau Mutation ◽  
Tau Aggregation ◽  
Frontotemporal Dementias ◽  
Tau Acetylation

AbstractAlzheimer’s disease is the leading cause of dementia and a defining hallmark is the progressive brain deposition of tau aggregates. The insidious accumulation of brain tau inclusions is also involved in a group of neurodegenerative diseases termed frontotemporal dementias. In all of these disorders, tau aggregates are enriched in post-translational modifications including acetylation, which has recently been identified at multiple sites. While most evidence suggest that tau acetylation is detrimental and promotes tau aggregation, a few studies support that tau acetylation within the KXGS motif can be protective and inhibit tau aggregation. To model site-specific acetylation at K259, K290, K321, and K353, acetylmimetics were created by mutating lysine to glutamine residues, which approximates size and charge of acetylation. HEK293T cells were transfected to express wild type tau, tau pathogenic mutations (P301L and P301L/S320F) or tau acetylmimetics and assessed by cell-based assays for microtubule binding and tau aggregation. Acetylmimetics within the KXGS motif (K259Q, K290Q, K321Q, K353Q) leads to significant decreased tau–microtubule interactions. Acetylmimetics K321Q and K353Q within the context of the pathogenic P301L tau mutation strongly inhibited prion-like seeded aggregation. This protective effect was confirmed to decrease intrinsic aggregation of P301L/S320F tau double mutation. Surprisingly, K321Q and K353Q acetylmimetics altered the conformational structure of P301L/S320F tau to extensively impair Thioflavin S binding. Site-specific acetylation of tau at K321 and K353 could represent a natural protective mechanism against tau aggregation and could be a potential therapeutic target.

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.

The challenge of detecting modifications on proteins

2020 ◽  
Vol 64 (1) ◽  
pp. 135-153 ◽  
Author(s):  
Lauren Elizabeth Smith ◽  
Adelina Rogowska-Wrzesinska
Keyword(s):  
Mass Spectrometry ◽  
Protein Function ◽  
Chemical Properties ◽  
Lysine Acetylation ◽  
Mass Determination ◽  
Post Translational Modifications ◽  
Site Specific ◽  
The Common

Abstract Post-translational modifications (PTMs) are integral to the regulation of protein function, characterising their role in this process is vital to understanding how cells work in both healthy and diseased states. Mass spectrometry (MS) facilitates the mass determination and sequencing of peptides, and thereby also the detection of site-specific PTMs. However, numerous challenges in this field continue to persist. The diverse chemical properties, low abundance, labile nature and instability of many PTMs, in combination with the more practical issues of compatibility with MS and bioinformatics challenges, contribute to the arduous nature of their analysis. In this review, we present an overview of the established MS-based approaches for analysing PTMs and the common complications associated with their investigation, including examples of specific challenges focusing on phosphorylation, lysine acetylation and redox modifications.

scholarly journals Phosphorylation of the Regulators, a Complex Facet of NF-κB Signaling in Cancer

Biomolecules ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Aishat Motolani ◽  
Matthew Martin ◽  
Mengyao Sun ◽  
Tao Lu
Keyword(s):  
Transcription Factor ◽  
Cardiovascular Diseases ◽  
Cancer Progression ◽  
Nuclear Factor Kappa B ◽  
Nuclear Factor ◽  
Malignant Diseases ◽  
Future Perspectives ◽  
Post Translational Modifications ◽  
Site Specific

The nuclear factor kappa B (NF-κB) is a ubiquitous transcription factor central to inflammation and various malignant diseases in humans. The regulation of NF-κB can be influenced by a myriad of post-translational modifications (PTMs), including phosphorylation, one of the most popular PTM formats in NF-κB signaling. The regulation by phosphorylation modification is not limited to NF-κB subunits, but it also encompasses the diverse regulators of NF-κB signaling. The differential site-specific phosphorylation of NF-κB itself or some NF-κB regulators can result in dysregulated NF-κB signaling, often culminating in events that induce cancer progression and other hyper NF-κB related diseases, such as inflammation, cardiovascular diseases, diabetes, as well as neurodegenerative diseases, etc. In this review, we discuss the regulatory role of phosphorylation in NF-κB signaling and the mechanisms through which they aid cancer progression. Additionally, we highlight some of the known and novel NF-κB regulators that are frequently subjected to phosphorylation. Finally, we provide some future perspectives in terms of drug development to target kinases that regulate NF-κB signaling for cancer therapeutic purposes.

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 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.

scholarly journals A Peptidoform Matching Strategy in Bottom-Up Proteomics for Studying Functions of Post-Translational Modifications

2021 ◽  
Author(s):  
Yansheng Liu
Keyword(s):  
Quantitative Analysis ◽  
Relevant Information ◽  
Previous Literature ◽  
Biological Functions ◽  
Biological Investigation ◽  
Bottom Up ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Specific Approach ◽  
Matching Strategy

Protein translational modifications (PTMs) generate an enormous, but as yet undetermined, expansion of the expressed proteoforms. In this Viewpoint, we firstly differentiate the concepts of proteoform and peptidoform by reviewing and discussing previous literature. We show that the current PTM biological investigation and annotation largely follow a PTM site-specific rather than proteoform-specific approach. We further illustrate a potentially useful matching strategy in which a particular “modified peptidoform” is matched to the corresponding “unmodified peptidoform” as a reference for the quantitative analysis between samples and conditions. We suggest this strategy could provide directly relevant information for learning the PTM site-specific biological functions. Accordingly, we advocate for the wider use of the nomenclature “peptidoform” in the future bottom-up proteomic studies.

scholarly journals Site-Specific Conversion of Cysteine in a Protein to Dehydroalanine Using 2-Nitro-5-thiocyanatobenzoic Acid

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2619
Author(s):  
Yuchen Qiao ◽  
Ge Yu ◽  
Sunshine Z. Leeuwon ◽  
Wenshe Ray Liu
Keyword(s):  
Functional Annotation ◽  
Chemical Reagent ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Internal Region ◽  
Hydrolysis Products ◽  
Starting Point ◽  
Michael Acceptor ◽  
Formation Method ◽  
High Yields

Dehydroalanine exists natively in certain proteins and can also be chemically made from the protein cysteine. As a strong Michael acceptor, dehydroalanine in proteins has been explored to undergo reactions with different thiolate reagents for making close analogues of post-translational modifications (PTMs), including a variety of lysine PTMs. The chemical reagent 2-nitro-5-thiocyanatobenzoic acid (NTCB) selectively modifies cysteine to form S-cyano-cysteine, in which the S–Cβ bond is highly polarized. We explored the labile nature of this bond for triggering E2 elimination to generate dehydroalanine. Our results indicated that when cysteine is at the flexible C-terminal end of a protein, the dehydroalanine formation is highly effective. We produced ubiquitin and ubiquitin-like proteins with a C-terminal dehydroalanine residue with high yields. When cysteine is located at an internal region of a protein, the efficiency of the reaction varies with mainly hydrolysis products observed. Dehydroalanine in proteins such as ubiquitin and ubiquitin-like proteins can serve as probes for studying pathways involving ubiquitin and ubiquitin-like proteins and it is also a starting point to generate proteins with many PTM analogues; therefore, we believe that this NTCB-triggered dehydroalanine formation method will find broad applications in studying ubiquitin and ubiquitin-like protein pathways and the functional annotation of many PTMs in proteins such as histones.

scholarly journals Salicylaldehyde ester-mediated protein semi-synthesis enables studies on the tetra-acetylation of HMGB1

2021 ◽  
Author(s):  
Tongyao Wei ◽  
Jiamei Liu ◽  
Yi Tan ◽  
Ruohan Wei ◽  
Jinzheng Wang ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
High Purity ◽  
Protein Function ◽  
Protein A ◽  
High Mobility ◽  
High Mobility Group ◽  
Biological Study ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Synthesis Strategy

To answer how protein post-translational modifications (PTMs) affect protein function, conformation, sta-bility, localization and interaction with binders remains important in the biological study. However, the re-lated study has been dramatically hindered by the difficulty in obtaining homogenous proteins with site-specific PTMs of interest. Herein, we introduce a protein semi-synthesis strategy via salicylaldehyde ester-mediated chemical ligations (Ser/Thr ligation and Cys/Pen ligation). This methodology has enabled us to generate Lys (2/6/7/11) tetra-acetylated HMGB1 (high-mobility group box 1) protein, a 25 kDa proin-flammatory protein, in high purity. Further studies revealed that the tetra-acetylation may represent a regu-latory switch to control the HMGB1 signaling pathway by abolishing its interaction with lipopolysaccha-ride (LPS) and accelerating its degradation, consequently preventing cells from pyroptosis and lethality upon infectious injury.

scholarly journals Non-Canonical Roles of Tau and Their Contribution to Synaptic Dysfunction

2021 ◽  
Vol 22 (18) ◽  
pp. 10145
Author(s):  
Giacomo Siano ◽  
Chiara Falcicchia ◽  
Nicola Origlia ◽  
Antonino Cattaneo ◽  
Cristina Di Primio
Keyword(s):  
Tau Protein ◽  
Neurodegenerative Disorders ◽  
Neuronal Degeneration ◽  
Synaptic Dysfunction ◽  
Cell Soma ◽  
Post Translational Modifications ◽  
Synaptic Homeostasis ◽  
Wide Range ◽  
And Function ◽  
Tau Aggregation

Tau plays a central role in a group of neurodegenerative disorders collectively named tauopathies. Despite the wide range of diverse symptoms at the onset and during the progression of the pathology, all tauopathies share two common hallmarks, namely the misfolding and aggregation of Tau protein and progressive synaptic dysfunctions. Tau aggregation correlates with cognitive decline and behavioural impairment. The mechanistic link between Tau misfolding and the synaptic dysfunction is still unknown, but this correlation is well established in the human brain and also in tauopathy mouse models. At the onset of the pathology, Tau undergoes post-translational modifications (PTMs) inducing the detachment from the cytoskeleton and its release in the cytoplasm as a soluble monomer. In this condition, the physiological enrichment in the axon is definitely disrupted, resulting in Tau relocalization in the cell soma and in dendrites. Subsequently, Tau aggregates into toxic oligomers and amyloidogenic forms that disrupt synaptic homeostasis and function, resulting in neuronal degeneration. The involvement of Tau in synaptic transmission alteration in tauopathies has been extensively reviewed. Here, we will focus on non-canonical Tau functions mediating synapse dysfunction.

scholarly journals The post-translational modification landscape of commercial beers

2021 ◽  
Author(s):  
Edward D. Kerr ◽  
Christopher H. Caboche ◽  
Cassandra L. Pegg ◽  
Toan K. Phung ◽  
Claudia Gonzalez Viejo ◽  
...  
Keyword(s):  
Site Specificity ◽  
Foam Formation ◽  
Post Translational Modification ◽  
Post Translational Modifications ◽  
Site Specific ◽  
Quality Properties ◽  
Surface Active ◽  
Molecular Complexity ◽  
Very High ◽  
High Diversity

AbstractBeer is one of the most popular beverages worldwide. As a product of variable agricultural ingredients and processes, beer has high molecular complexity. We used DIA/SWATH-MS to investigate the proteomic complexity and diversity of 24 commercial Australian beers. While the overall complexity of the beer proteome was modest, with contributions from barley and yeast proteins, we uncovered a very high diversity of post-translational modifications (PTMs), especially proteolysis, glycation, and glycosylation. Proteolysis was widespread throughout barley proteins, but showed clear site-specificity. Oligohexose modifications were common on lysines in barley proteins, consistent with glycation by maltooligosaccharides released from starch during malting or mashing. O-glycosylation consistent with oligomannose was abundant on secreted yeast glycoproteins. We developed and used data analysis pipelines to efficiently extract and quantify site-specific PTMs from SWATH-MS data, and showed incorporating these features into proteomic analyses extended analytical precision. We found that the key differentiator of the beer glyco/proteome was the brewery, followed by the beer style. Targeting our analyses to beers from a single brewery, Newstead Brewing Co., allowed us to identify beer style-specific features of the glyco/proteome. Specifically, we found that proteins in darker beers tended to have low glycation and high proteolysis. Finally, we objectively quantified features of foam formation and stability, and showed that these quality properties correlated with the concentration of abundant surface-active proteins from barley and yeast.

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