Abnormal changes of neuronal Tau protein, such as phosphorylation and aggregation, are considered hallmarks of cognitive deficits in Alzheimer's disease. Abnormal phosphorylation is thought to precede aggregation and therefore to promote aggregation, but the nature and extent of phosphorylation remain ill-defined. Tau contains $\sim$85 potential phosphorylation sites, which can be phosphorylated by various kinases because the unfolded structure of Tau makes them accessible. However, methodological limitations (e.g. in MS of phosphopeptides, or antibodies against phosphoepitopes) led to conflicting results regarding the extent of Tau phosphorylation in cells. Here we present results from a new approach based on native MS of intact Tau expressed in eukaryotic cells (Sf9). The extent of phosphorylation is heterogeneous, up to $\sim$20 phosphates per molecule distributed over 51 sites. The medium phosphorylated fraction P(m) showed overall occupancies of $\sim$8 P(i) (± 5) with a bell-shaped distribution; the highly phosphorylated fraction P(h) had 14 P(i) (± 6). The distribution of sites was highly asymmetric (with 71\% of all P-sites in the C-terminal half of Tau). All sites were on Ser or Thr residues, but none were on Tyr. Other known posttranslational modifications were near or below our detection limit (e.g. acetylation, ubiquitination). These findings suggest that normal cellular Tau shows a remarkably high extent of phosphorylation, whereas other modifications are nearly absent. This implies that abnormal phosphorylations at certain sites may not affect the extent of phosphorylation significantly and do not represent hyperphosphorylation. By implication, the pathological aggregation of Tau is not likely a consequence of high phosphorylation.
%0 Journal Article
%1 drepperCombinatorialNativeMS2020a
%A Drepper, Friedel
%A Biernat, Jacek
%A Kaniyappan, Senthilvelrajan
%A Meyer, Helmut E.
%A Mandelkow, Eva Maria
%A Warscheid, Bettina
%A Mandelkow, Eckhard
%C United States
%D 2020
%J The Journal of biological chemistry
%K (MS),native (Tau),tau *Protein Acid Homology,Tandem Liquid/*methods,Humans,LC-MS,mass Mass Post-Translational,Alzheimer's Processing Proteins/*chemistry/*metabolism,to_read Sequence,Chromatography Spectrometry/*methods,Tau aggregation,Sequence disease,Amino mass protein spectrometry spectrometry,phosphorylation,Phosphorylation,protein
%N 52
%P 18213--18225
%R 10.1074/jbc.RA120.015882
%T A Combinatorial Native MS and LC-MS/MS Approach Reveals High Intrinsic Phosphorylation of Human Tau but Minimal Levels of Other Key Modifications.
%V 295
%X Abnormal changes of neuronal Tau protein, such as phosphorylation and aggregation, are considered hallmarks of cognitive deficits in Alzheimer's disease. Abnormal phosphorylation is thought to precede aggregation and therefore to promote aggregation, but the nature and extent of phosphorylation remain ill-defined. Tau contains $\sim$85 potential phosphorylation sites, which can be phosphorylated by various kinases because the unfolded structure of Tau makes them accessible. However, methodological limitations (e.g. in MS of phosphopeptides, or antibodies against phosphoepitopes) led to conflicting results regarding the extent of Tau phosphorylation in cells. Here we present results from a new approach based on native MS of intact Tau expressed in eukaryotic cells (Sf9). The extent of phosphorylation is heterogeneous, up to $\sim$20 phosphates per molecule distributed over 51 sites. The medium phosphorylated fraction P(m) showed overall occupancies of $\sim$8 P(i) (± 5) with a bell-shaped distribution; the highly phosphorylated fraction P(h) had 14 P(i) (± 6). The distribution of sites was highly asymmetric (with 71\% of all P-sites in the C-terminal half of Tau). All sites were on Ser or Thr residues, but none were on Tyr. Other known posttranslational modifications were near or below our detection limit (e.g. acetylation, ubiquitination). These findings suggest that normal cellular Tau shows a remarkably high extent of phosphorylation, whereas other modifications are nearly absent. This implies that abnormal phosphorylations at certain sites may not affect the extent of phosphorylation significantly and do not represent hyperphosphorylation. By implication, the pathological aggregation of Tau is not likely a consequence of high phosphorylation.
@article{drepperCombinatorialNativeMS2020a,
abstract = {Abnormal changes of neuronal Tau protein, such as phosphorylation and aggregation, are considered hallmarks of cognitive deficits in Alzheimer's disease. Abnormal phosphorylation is thought to precede aggregation and therefore to promote aggregation, but the nature and extent of phosphorylation remain ill-defined. Tau contains {$\sim$}85 potential phosphorylation sites, which can be phosphorylated by various kinases because the unfolded structure of Tau makes them accessible. However, methodological limitations (e.g. in MS of phosphopeptides, or antibodies against phosphoepitopes) led to conflicting results regarding the extent of Tau phosphorylation in cells. Here we present results from a new approach based on native MS of intact Tau expressed in eukaryotic cells (Sf9). The extent of phosphorylation is heterogeneous, up to {$\sim$}20 phosphates per molecule distributed over 51 sites. The medium phosphorylated fraction P(m) showed overall occupancies of {$\sim$}8 P(i) ({\textpm} 5) with a bell-shaped distribution; the highly phosphorylated fraction P(h) had 14 P(i) ({\textpm} 6). The distribution of sites was highly asymmetric (with 71\% of all P-sites in the C-terminal half of Tau). All sites were on Ser or Thr residues, but none were on Tyr. Other known posttranslational modifications were near or below our detection limit (e.g. acetylation, ubiquitination). These findings suggest that normal cellular Tau shows a remarkably high extent of phosphorylation, whereas other modifications are nearly absent. This implies that abnormal phosphorylations at certain sites may not affect the extent of phosphorylation significantly and do not represent hyperphosphorylation. By implication, the pathological aggregation of Tau is not likely a consequence of high phosphorylation.},
added-at = {2024-05-17T13:01:35.000+0200},
address = {United States},
author = {Drepper, Friedel and Biernat, Jacek and Kaniyappan, Senthilvelrajan and Meyer, Helmut E. and Mandelkow, Eva Maria and Warscheid, Bettina and Mandelkow, Eckhard},
biburl = {https://www.bibsonomy.org/bibtex/26137d9537c164b0a494295ffa598a91f/warscheidlab},
copyright = {{\copyright} 2020 Drepper et al.},
doi = {10.1074/jbc.RA120.015882},
interhash = {358862c7ae0bebf0b5ecec686efe0fd5},
intrahash = {6137d9537c164b0a494295ffa598a91f},
issn = {1083-351X 0021-9258},
journal = {The Journal of biological chemistry},
keywords = {(MS),native (Tau),tau *Protein Acid Homology,Tandem Liquid/*methods,Humans,LC-MS,mass Mass Post-Translational,Alzheimer's Processing Proteins/*chemistry/*metabolism,to_read Sequence,Chromatography Spectrometry/*methods,Tau aggregation,Sequence disease,Amino mass protein spectrometry spectrometry,phosphorylation,Phosphorylation,protein},
langid = {english},
month = dec,
number = 52,
pages = {18213--18225},
pmcid = {PMC7939451},
pmid = {33106314},
timestamp = {2024-05-17T13:01:35.000+0200},
title = {A Combinatorial Native {{MS}} and {{LC-MS}}/{{MS}} Approach Reveals High Intrinsic Phosphorylation of Human {{Tau}} but Minimal Levels of Other Key Modifications.},
volume = 295,
year = 2020
}