Recognition of the minimal epitope of monoclonal antibody Tau‐1 depends upon the presence of a phosphate group but not its location

Szendrei, Gyorgyi I.; Lee, V. M.‐Y.; Ötvös, László

doi:10.1002/jnr.490340212

Cited by 196 publications

(111 citation statements)

References 31 publications

Supporting

Mentioning

105

Contrasting

Order By: Relevance

“…The conformation-modifying effect of the aspartic-acidbond isomerization is similar to that of carbohydrate incorporation into synthetic peptides and clearly different from that of phosphorylation. While phosphorylation is heavily sequence dependent and clear-cut conclusions are difficult to draw (Lang et al, 1992;Szendrei et al, 1993), we showed earlier that internal glycosylation of synthetic peptides generally breaks helices, and /I turns are formed after glycosyla- tion of T-cell epitopic a-helical peptides (Otvos et al, 1991). Similarly to the P-aspartyl peptides, external glycosylation did not affect the secondary structure of the peptides .…”

Section: Discussionmentioning

confidence: 99%

Aspartate‐Bond Isomerization Affects the Major Conformations of Synthetic Peptides

Szendrei¹,

Fabian

Mantsch

et al. 1994

European Journal of Biochemistry

View full text Add to dashboard Cite

The aspartic acid bond changes to an p-aspartate bond frequently as a side-reaction during peptide synthesis and often as a post-translational modification of proteins. The formation of paspartate bonds is reported to play a major role not only in protein metabolism, activation and deactivation, but also in pathological processes such as deposition of the neuritic plaques of Alzheimer's disease. Recently, we reported how conformational changes following the aspartic-acidbond isomerization may help the selective aggregation and retention of the amyloid p peptide in affected brains (Fabian et al., 1994). In the current study we used circular dichroism, Fouriertransform infrared spectroscopy, and molecular modeling to characterize the general effect of the , & aspartate-bond formation on the conformation of five sets of synthetic model peptides. Each of the non-modified, parent peptides has one of the major secondary structures as the dominant spectroscopically determined conformation: a type I p turn, a type I1 p turn, short segments of a or 3,, helices, or extended p strands. We found that both types of turn structures are stabilized by the aspartic acid-bond isomerization. The isomerization at a terminal position did not affect the helix propensity, but placing it in mid-chain broke both the helix and the /?-pleated sheet with the formation of reverse turns. The alteration of the geometry of the lowest energy reverse turn was also supported by molecular dynamics calculations. The tendency of the aspartic acid-bond isomerization to stabilize turns is very similar to the effect of incorporating sugars into synthetic peptides and suggests a common feature of these post-translational modifications in defining the secondary structure of protein fragments.

show abstract

Section: Discussionmentioning

confidence: 99%

Aspartate‐Bond Isomerization Affects the Major Conformations of Synthetic Peptides

Szendrei¹,

Fabian

Mantsch

et al. 1994

European Journal of Biochemistry

View full text Add to dashboard Cite

show abstract

“…Equal amounts of protein from each sample were diluted in 2ϫ SDS stop buffer (0.5 M Tris-Cl, pH 6.8, 10% SDS, 10 mM EGTA, 10 mM EDTA, 25 mM dithiothreitol, 10% glycerol, 0.01% bromphenol blue), incubated in a boiling water bath for 5 min, electrophoresed on 10% SDS-polyacrylamide gels, transferred to nitrocellulose membrane, and probed with the indicated antibodies. The tau antibodies used in this study were Tau5 and 5A6 (Tau5 from Dr. L. Binder), which are phosphoindependent tau antibodies (37, 38), Tau-1 (from Dr. L. Binder), which recognizes tau only when Ser-195, Ser-198, Ser-199, Ser-202, and Thr-205 (numbered according to the longest human brain tau isoform (10)) are not phosphorylated (39,40), PHF-1 (from Dr. P. Davies), which recognizes tau phosphorylated at Ser-396/404 (41), and AT180 (Endogen), which recognizes tau phosphorylated at Thr-231 (42,43). An antibody to ␤-actin (Chemicon) was also used.…”

Section: Methodsmentioning

confidence: 99%

Mutant (R406W) Human Tau Is Hyperphosphorylated and Does Not Efficiently Bind Microtubules in a Neuronal Cortical Cell Model

Krishnamurthy

Johnson

2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

Frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17) is an autosomal dominant neurodegenerative disorder caused by mutations in the gene that encodes for tau, a microtubule-binding protein. Neuropathologically the disease is characterized by extensive neuronal loss in the frontal and temporal lobes and the filamentous accumulation of hyperphosphorylated tau. The R406W missense mutation was originally described in an American and a Dutch family. Although R406W tau is hyperphosphorylated in FTDP-17 cases, R406W tau expressed in cell model systems has not shown increased phosphorylation. The purpose of this study was to establish a neuronal model system in which the phosphorylation of R406W tau is increased and thus more representative of the in vivo situation. To accomplish this goal immortalized mouse cortical cells that express low levels of endogenous tau were stably transfected with human wild type or R406W tau. In this neuronal model R406W tau was more highly phosphorylated at numerous epitopes and showed decreased microtubule binding compared with wild type tau, an effect that could be reversed by dephosphorylation. In addition the expression of R406W tau in the cortical cells resulted in increased cell death as compared with wild type tau-expressing cells when the cells were exposed to an apoptotic stressor. These results indicate that in an appropriate cellular context R406W tau is hyperphosphorylated, which leads to decreased microtubule binding. Furthermore, expression of R406W tau sensitized cells to apoptotic stress, which may contribute to the neuronal cell loss that occurs in this FTDP-17 tauopathy.Frontotemporal dementia (FTD) 1 refers to a group of neurological disorders that are characterized clinically by progressive behavioral changes and neuropathologically by neuronal loss in the frontal and temporal lobes and the presence of filamentous deposits of abnormally hyperphosphorylated tau protein in neurons and/or glial cells (1-4). FTDs occur mainly as sporadic cases but also as familial forms with an autosomal dominant mode of inheritance and age-dependent penetrance (1). In 1998 it was demonstrated that several familial FTDs were due to mutations in the tau gene and have been referred to as frontotemporal dementia and Parkinsonism linked to chromosome 17 (FTDP-17) (5-7). Since these initial discoveries, additional tau mutations have been described in frontotemporal dementia families, and presently over 25 mutations in the tau gene have been identified (8, 9). They include missense mutations in coding regions, amino acid deletions, and intronic mutations in the region following exon 10. The mutations may be divided into two main groups, those that affect alternative splicing of exon 10, leading to changes in the ratio of tau mRNAs with or without exon 10, and thus the proportion of tau with three microtubule binding repeats versus tau with four microtubule binding repeats, and missense mutations.Tau is a microtubule-associated protein that facilitates microtubule assembly an...

show abstract

“…Tau-5 (from Dr. L. Binder) recognizes tau epitopes independent of their phosphorylation state (24). Tau-1 (from Dr. L. Binder) recognizes tau dephosphorylated at residues 189 -207 (25,26). 12E8 (from Dr. P. Seubert) recognizes Ser 262/356 -phosphorylated tau (27).…”

Section: Methodsmentioning

confidence: 99%

Transient Increases in Intracellular Calcium Result in Prolonged Site-selective Increases in Tau Phosphorylation through a Glycogen Synthase Kinase 3β-dependent Pathway

Hartigan

Johnson

1999

Journal of Biological Chemistry

126

View full text Add to dashboard Cite

Calcium is a universal intracellular signaling molecule. Through variations in both the amplitude and frequency of intracellular calcium increases, the same calcium ion can elicit different responses. In this report, we investigated the effect of a calcium transient, lasting 2-5 min, on alterations in the phosphorylation state of the cytoskeletal protein, tau. Transient increases in calcium result in a prolonged (1-4 h) ϳ60% increase in tau phosphorylation at the Tau-1 epitope. These increases in tau phosphorylation appear to be more dependent upon the duration of the increase in intracellular calcium and less on the amplitude. The calcium-induced increases in tau phosphorylation are not dependent upon protein synthesis,norareproteinkinaseCorcalcium/calmodulindependent protein kinase II involved in the response. However, the calcium-induced increase in tau phosphorylation was inhibited by lithium, a noncompetitive inhibitor of glycogen synthase kinase-3␤ (GSK-3␤), and by the tyrosine kinase inhibitor, genistein. Furthermore, transient increases in calcium resulted in a prolonged increase in GSK-3␤ tyrosine phosphorylation concomitant with the increase in tau phosphorylation. Therefore, this study is the first to indicate that transient increases in intracellular calcium result in increased tyrosine phosphorylation and activation of GSK-3␤ which subsequently results in a sustained increase in the phosphorylation state of tau.Calcium is an important intracellular messenger for neuronal signaling pathways. Cytoplasmic calcium concentrations fluctuate when extracellular calcium enters the cell and/or when calcium is released from intracellular stores, and both temporal and spatial aspects of the calcium signal are important in regulating cellular responses (1, 2). The regulation of specific protein kinases and phosphatases by different calcium signals is likely to play a role in numerous physiological and pathological processes. For example, recent studies have demonstrated that increases in intracellular calcium differentially altered phosphorylation of the microtubule-associated protein, MAP-2, in neonatal and adult rat hippocampal slices (3). These findings suggest that mature and immature neurons respond differently to calcium signals and this in turn results in specific phospho-dependent changes in the cytoskeleton. Considering these previous findings, it is likely that the phosphorylation and function of other cytoskeletal proteins are modulated by specific calcium signals.Tau, a family of microtubule-associated proteins produced by alternative splicing of a single gene, is a prominent phosphoprotein of the neuronal cytoskeleton. The classical function of tau is to promote microtubule nucleation and assembly, as well as to stabilize microtubules (for review, see Ref. 4). However, tau also appears to be involved in other cellular functions, including signal transduction (5-7) and organelle transport (8, 9). It has been well documented that increasing the phosphorylation state of tau greatly reduces its ability ...

show abstract

Recognition of the minimal epitope of monoclonal antibody Tau‐1 depends upon the presence of a phosphate group but not its location

Cited by 196 publications

References 31 publications

Aspartate‐Bond Isomerization Affects the Major Conformations of Synthetic Peptides

Aspartate‐Bond Isomerization Affects the Major Conformations of Synthetic Peptides

Mutant (R406W) Human Tau Is Hyperphosphorylated and Does Not Efficiently Bind Microtubules in a Neuronal Cortical Cell Model

Transient Increases in Intracellular Calcium Result in Prolonged Site-selective Increases in Tau Phosphorylation through a Glycogen Synthase Kinase 3β-dependent Pathway

Contact Info

Product

Resources

About