Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10636 (tau protein)
 5,110 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The recent re-discovery of axonal damage in multiple sclerosis has led to a renewed interest in neurodegenerative mechanisms of the disease. Transected or injured axons release several molecules from their proximal extremity into the intercellular space. Although these molecules can be measured, however, a biological marker of axonal and neuronal degeneration is still lacking. Cytoskeleton structural proteins like actin, tubulin, L-neurofilaments and tau protein, axon-specific antibodies, other neuronal or glial proteins like S-100, 14-3-3 and glial fibrillary acid protein, neuronal specific enolase, and nitric oxide and its metabolites are some of the putative markers that deserve further investigation and validation. At present, none of them fulfils the criteria of applicability in clinical practice, and the levels of N-acetylaspartate determined by magnetic resonance spectroscopy remain the most reliable measure of axonal damage.
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PMID:Biological indicators of the neurodegenerative phase of multiple sclerosis. 1465 89

Recently it has been shown that axonal damage occurs in all stages of multiple sclerosis (MS) and can be detected very early in the course of the disease. Axonal pathology has been related to the inflammatory demyelinating environment, but its dependence on inflammation is still unknown. We measured tau protein and 14-3-3, two intracellular proteins expressed in neurons and glial cells, in the cerebrospinal fluid (CSF) of 114 patients with MS, in 79 patients with other inflammatory neurological diseases (IND) and in the CSF of 60 patients with non-inflammatory neurological diseases (NIND) as controls. Concentrations of tau protein and 14-3-3 were measured by enzymelinked immunoassay and were correlated to the following immune parameters in the CSF: leukocyte cell count, total protein, albumin CSF/serum ratio as a marker of disruption of the blood-brain barrier, immunoglobulin (IgG concentrations and IgG index as an indicator for intrathecal synthesis of IgG in the CSF). Both in MS and IND tau protein levels were significantly higher than in NIND (p<0.05). In MS patients levels of tau protein were positively correlated with the IgG index (p<0.05) and this association was present in both relapsing remitting MS (RRMS) (p<0.05) and progressive MS (p<0.05). Tau and 14-3-3 were also correlated with the IgG index in patients with IND (p<0.05). These findings strengthen the hypothesis that inflammation may be at least in part responsible for the axonal damage observed in MS patients.
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PMID:Tau protein and 14-3-3 are elevated in the cerebrospinal fluid of patients with multiple sclerosis and correlate with intrathecal synthesis of IgG. 1508 85

Immunolocalization of 14-3-3 proteins in Alzheimer's disease (AD) brains was investigated using isoform-specific antibodies. Weak granular immunoreactivity of 14-3-3 proteins was found in neuronal cytoplasm in control subjects and AD brains. Both intracellular and extracellular neurofibrillary tangles (NFTs), as well as neuropil thread-like structures, were immunopositive for 14-3-3 proteins. This was corroborated by triple-fluorolabeling method visualizing paired helical filament (PHF) tau and 14-3-3 epitopes in relation to fibrillary state detected by thiazin red. Pretangle neurons (positive for PHF-tau without fibrillary structure detected by thiazin red) only contained fine granular immunoreactivity (IR) of 14-3-3, which was similarly found in unaffected neurons. Granular cytoplasmic IR of 14-3-3 proteins in pretangle neurons was not colocalized to granular tau-like IR, which suggests that participation of 14-3-3 proteins in NFT formation was restricted to its later stages. Its zeta isoform was most prominent in these NFTs, suggesting that this isoform is a major component involved in the formation of NFTs. In contrast, IR of epsilon isoform was found in the neuropil of the hippocampus and that of sigma isoform was localized to granule cells of the dentate gyrus in AD brains, as seen in the age-matched controls. Expression of 14-3-3 proteins were found to be highly variable and dependent on their isoforms, regions and cell types. Molecular, as well as topographical, dissection of 14-3-3 proteins will provide us with an improved understanding of this molecule in normal and pathological conditions.
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PMID:14-3-3 proteins and zeta isoform containing neurofibrillary tangles in patients with Alzheimer's disease. 1523 3

The microtubule-associated protein tau is found aggregated into paired helical filaments in the intraneuronal neurofibrillary tangle deposits of victims of Alzheimer's disease (AD) and other related dementias. Tau contains a repeat domain consisting of three or four 31-32-residue imperfect repeats that forms the core of tau filaments and is capable of self-assembling into filaments in vitro. We have used high-resolution NMR spectroscopy to characterize the structural properties of the three-repeat domain of tau at the level of individual residues. We find that three distinct regions of the polypeptide corresponding to previously mapped microtubule interaction sites exhibit a preference for helical conformations, suggesting that these sites adopt a helical structure when bound to microtubules. In addition, we directly observe a marked preference for extended or beta-strand-like conformations in a stretch of residues between two of the helical regions, which corresponds closely to a region previously implicated as an early site of beta-strand structure formation and intermolecular interactions leading to paired helical filament (PHF) formation. This observation supports the idea that this region of the protein plays a crucial role in the formation of tau aggregates. We further show that disulfide-bond-mediated dimer formation does not affect and is not responsible for the observed structural preferences of the protein. Our results provide the first high-resolution view of the structural properties of the protein tau, are consistent with an important role for beta structure in PHF formation, and may also help explain recent reports that tau filaments contain helical structure.
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PMID:Residual structure in the repeat domain of tau: echoes of microtubule binding and paired helical filament formation. 1565 59

Microtubule associated protein tau is abnormally phosphorylated in Alzheimer's disease (AD) and aggregates as paired helical filaments (PHFs) in neurofibrillary tangles (NFTs), which are one of the pathological signatures of AD and their presence correlates with severity of dementia. Dysfunction of protein phosphatases in the effected neurons is proposed to be a possible causative factor to AD development. We show here that the pattern of tau phosphorylation correlates with the decline of memory retention ability in rat brain. In our study, we have chosen 55 rats of full age to conduct the discrimination between their normal and low ability of memory retention in one-trial step-down test. It was found that among rats that developed the impairment in memory retention in step-down inhibitory avoidance task, tau protein in their hippocampus was hyperphosohorylated at Thr231/Ser235 (M4) sites of tau, and the significantly increased expression of PP-1 and the decreased one of PP-2B were also determined by Western blot and/or immunohistochemistry. It is implicated that: (1) the hyperphosphorylation of tau at M4 sites may be crucial to affect the memory retention of elder rats; (2) PP-1 might participate in the regulation of phosphorylation at Thr231 and Ser235 epitope of tau in vivo, and the up-regulation of PP-1 content could be in relation to tau hyperphosphorylation at Thr231/Ser235 sites of brain tau and the worse memory retention of rats indirectly; and (3) the decline of PP-2B content could induced the hyperphosphorylation of tau at M4 sides in vivo.
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PMID:Specific tau phosphorylation sites in hippocampus correlate with impairment of step-down inhibitory avoidance task in rats. 1569 94

The authors describe 12 neuroleptic-treated patients with dementia of various etiologies who showed CSF elevation of phosphorylated 14-3-3zeta and normal tau protein levels. This contrasted with elevated amounts of 14-3-3 gamma, epsilon, and unphosphorylated zeta coupled to high tau protein levels in Creutzfeldt-Jakob disease and negative 14-3-3 assay in drug-free patients with dementia. Characterization of CSF 14-3-3 isoforms and determination of tau protein level can help to distinguish different etiologies of dementia.
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PMID:Phosphorylated 14-3-3zeta protein in the CSF of neuroleptic-treated patients. 1588 27

Microtubule-stabilizing and -destabilizing proteins play a crucial role in regulating the dynamic instability of microtubules during neuronal development and synaptic transmission. The microtubule-destabilizing protein SCG10 is a neuron-specific protein implicated in neurite outgrowth. The SCG10 protein is significantly reduced in mature neurons, suggesting that its expression is developmentally regulated. In contrast, the microtubule-stabilizing protein tau is expressed in mature neurons and its function is essential for the maintenance of neuronal polarity and neuronal survival. Thus, the establishment and maintenance of neuronal polarity may down-regulate the protein level/function of SCG10. In this report, we show that treatment of PC12 cells and neuroblastoma cells with the microtubule-stabilizing drug Taxol induced a rapid degradation of the SCG10 protein. Consistently, overexpression of tau protein in neuroblastoma cells also induced a reduction in SCG10 protein levels. Calpain inhibitor MDL-28170, but not caspase inhibitors, blocked a significant decrease in SCG10 protein levels. Collectively, these results indicate that tau overexpression and Taxol treatment induced a calpain-dependent degradation of the microtubule-destabilizing protein SCG10. The results provide evidence for the existence of an intracellular mechanism involved in the regulation of SCG10 upon microtubule stabilization.
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PMID:Taxol and tau overexpression induced calpain-dependent degradation of the microtubule-destabilizing protein SCG10. 1682 11

Polymorphic genes associated with Alzheimer's disease (see ) delineate a clearly defined pathway related to cerebral and peripheral cholesterol and lipoprotein homoeostasis. They include all of the key components of a glia/neurone cholesterol shuttle including cholesterol binding lipoproteins APOA1, APOA4, APOC1, APOC2, APOC3, APOD, APOE and LPA, cholesterol transporters ABCA1, ABCA2, lipoprotein receptors LDLR, LRP1, LRP8 and VLDLR, and the cholesterol metabolising enzymes CYP46A1 and CH25H, whose oxysterol products activate the liver X receptor NR1H2 and are metabolised to esters by SOAT1. LIPA metabolises cholesterol esters, which are transported by the cholesteryl ester transport protein CETP. The transcription factor SREBF1 controls the expression of most enzymes of cholesterol synthesis. APP is involved in this shuttle as it metabolises cholesterol to 7-betahydroxycholesterol, a substrate of SOAT1 and HSD11B1, binds to APOE and is tethered to LRP1 via APPB1, APBB2 and APBB3 at the cytoplasmic domain and via LRPAP1 at the extracellular domain. APP cleavage products are also able to prevent cholesterol binding to APOE. BACE cleaves both APP and LRP1. Gamma-secretase (PSEN1, PSEN2, NCSTN) cleaves LRP1 and LRP8 as well as APP and their degradation products control transcription factor TFCP2, which regulates thymidylate synthase (TS) and GSK3B expression. GSK3B is known to phosphorylate the microtubule protein tau (MAPT). Dysfunction of this cascade, carved out by genes implicated in Alzheimer's disease, may play a major role in its pathology. Many other genes associated with Alzheimer's disease affect cholesterol or lipoprotein function and/or have also been implicated in atherosclerosis, a feature of Alzheimer's disease, and this duality may well explain the close links between vascular and cerebral pathology in Alzheimer's disease. The definition of many of these genes as risk factors is highly contested. However, when polymorphic susceptibility genes belong to the same signaling pathway, the risk associated with multigenic disease is better related to the integrated effects of multiple polymorphisms of genes within the same pathway than to variants in any single gene [Wu, X., Gu, J., Grossman, H.B., Amos, C.I., Etzel, C., Huang, M., Zhang, Q., Millikan, R.E., Lerner, S., Dinney, C.P., Spitz, M.R., 2006. Bladder cancer predisposition: a multigenic approach to DNA-repair and cell-cycle-control genes. Am. J. Hum. Genet. 78, 464-479.]. Thus, the fact that Alzheimer's disease susceptibility genes converge on a clearly defined signaling network has important implications for genetic association studies.
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PMID:Convergence of genes implicated in Alzheimer's disease on the cerebral cholesterol shuttle: APP, cholesterol, lipoproteins, and atherosclerosis. 1697 41

Intraneuronal accumulation of hyperphosphorylated protein tau in paired helical filaments together with amyloid-beta peptide (Abeta) deposits confirm the clinical diagnosis of Alzheimer disease. A common cellular mechanism leading to the production of these potent toxins remains elusive. Here we show that, in cultured neurons, membrane depolarization induced a calcium-mediated transient phosphorylation of both microtubule-associated protein tau and amyloid precursor protein (APP), followed by a dephosphorylation of these proteins. Phosphorylation was mediated by glycogen synthase kinase 3 and cyclin-dependent kinase 5 protein kinases, while calcineurin was responsible for dephosphorylation. Following the transient phosphorylation of APP, intraneuronal Abeta accumulated and induced neurotoxicity. Phosphorylation of APP on Thr-668 was indispensable for intraneuronal accumulation of Abeta. Our data demonstrate that an increase in cytosolic calcium concentration induces modifications of neuronal metabolism of APP and tau, similar to those found in Alzheimer disease.
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PMID:Calcium-mediated transient phosphorylation of tau and amyloid precursor protein followed by intraneuronal amyloid-beta accumulation. 1708 46

Syncytiotrophoblast formation is affected by a number of pathological conditions and suppressed syncytiotrophoblast formation due to hypoxia may play a role in the pathogenesis of preeclampsia. However, the molecular basis of hypoxia-inhibited trophoblast syncytialization is poorly understood. To determine the effect of hypoxia on trophoblast syncytialization, a proteomic analysis was performed in the human cytotrophoblast cell line BeWo using two-dimensional electrophoresis and MALDI-TOF-TOF-MS. Hypoxia induced marked inhibition of BeWo cell fusion and differentiation. The proteomic profiling was established under hypoxia in BeWo cell syncytialization. The results showed that twenty proteins were significantly up-or down-regulated under hypoxia, compared with cells under normoxia. In response to hypoxia, three antioxidants, peroxiredoxin 1, peroxiredoxin 2 and 1-Cys peroxiredoxin, were down-regulated, two proteins involved in glycolysis pathway (malate dehydrogenase and enolase) were up-regulated. The expression of two members of the annexin family (annexin A2 and annexin A5) increased. We also found a decreased expression of 14-3-3 tau protein in hypoxia treated cells. Proteins implied in protein degradation and folding were also identified. The expression of two cytoskeleton components (keratin 1 and beta-actin) was found to be down-regulated. In addition, galectin-3 was up-regulated. These proteins have been implicated in regulating cellular oxidative stress, glycolysis, signal transduction, protein folding and degradation, cell mobility and cytoskeletal structure formation. Western blot analysis revealed that the levels of peroxiredoxin 1 and 14-3-3 tau decreased, whereas the levels of annexin A5 and annexin A2 increased in BeWo cells under hypoxia. These findings provided new insights into the molecular mechanisms in mediating cellular response to hypoxia in trophoblast syncytialization.
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PMID:Proteomic analysis of hypoxia-induced responses in the syncytialization of human placental cell line BeWo. 1709 81


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