Processes induced by tau expression in Sf9 cells have an axon-like microtubule organization.

Baas, Peter W.; Pienkowski, Thomaş P.; Kosik, Kenneth S.

doi:10.1083/jcb.115.5.1333

Cited by 144 publications

(105 citation statements)

References 52 publications

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“…From its axon-specific distribution in situ, tau has been implicated as having a role in the unique organization of axonal microtubules but direct evidence is still lacking. When tau is expressed in insect cells, microtubules are uniformly oriented like they are in the axon (54), but the same uniform orientation of microtubules results when MAP2 is expressed in this system (53). This may indicate that the uniform orientation of microtubules is the default state during process formation.…”

Section: An Axon-specific Function For Tau?mentioning

confidence: 80%

The tau proteins in neuronal growth and development

Brandt¹

1996

Front Biosci

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The neuronal microtubule-associated protein tau has been implicated as having a role in the outgrowth of neural processes and the development of neuronal polarity. In vitro, tau promotes microtubule assembly, stabilizes cellular microtubules, and affects their dynamic behavior. Antisense experiments using cultured neurons provided evidence for an essential role of tau in the development of axons. However, tau knockout mice turned out to be surprisingly healthy and developed neurons which were functionally and structurally almost normal. This raises the question of how essential tau is for neuronal development. In the first part of this paper, data on the function of tau as a microtubule assembly-promoting and stabilizing factor are reviewed. Then, studies investigating the role of tau in the development of neuronal polarity are discussed. In the last part, recent results which provide evidence for a role of tau not directly related to its activity on microtubule assembly are summarized. INTRODUCTIONNeurons are one of the most extreme cell types in that they contain processes which can reach a meter or longer and encompass more than 99% of the cellular volume. This requires the presence of a sophisticated molecular machinery in order to establish and maintain such a morphology. From

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Section: An Axon-specific Function For Tau?mentioning

confidence: 80%

The tau proteins in neuronal growth and development

Brandt¹

1996

Front Biosci

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“…Overexpression of tau in non-neuronal cells induces the formation of long neurite-like processes (52,53), whereas inhibiting tau expression using antisense tau resulted in the loss of neurite outgrowth and extension (54). In mouse cortical cells expression of wild type tau resulted in the formation of long processes/neurites, unlike the R406W mutant tau-expressing cells, which were much shorter, stubby projections.…”

Section: Cellular Localization Of Wild Type and Mutant R406wmentioning

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

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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...

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“…In cultured cerebellar neurons, antisense oligonucleotides for MAP2 and tau inhibit the incorporation of tubulin monomers into microtubules and prevent neurite elongation respectively (Caceres and Kosik, 1990). In non-neuronal cells, such as Sf9 cells, transfection of tau or MAP cDNA changes the cells from a normal rounded shape to a polarized morphology with an unbranched and elongated process (Baas et al, 1991;Knops et al, 1991;Boucher et al, 1999;Bélanger et al, 2001). These results indicate that neurite outgrowth of axons and dendrites depends on the assembly of microtubules, and that the polarization of the transfected non-neuronal cells, even in the absence of neuronal signalling machinery, is caused by the expression of intracellular tau or MAP.…”

Section: Agentmentioning

confidence: 99%

Disassembly of actin filaments by botulinum C₂ toxin and actin‐filament‐disrupting agents induces assembly of microtubules in human leukaemia cell lines

Uematsu

Kogo

Ohishi

2007

Biology of the Cell

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Background information. C 2 toxin produced by Clostridium botulinum types C and D ADP-ribosylates actin monomers and inactivates their polymerization activities. The disassembly of actin filaments by C 2 toxin induces a polarization of cultured human leukaemia cell lines.Results. The polarization induced by C 2 toxin was temperature dependent and was prevented by nocodazole, a microtubule-disrupting agent, whereas it was promoted by paclitaxel, a microtubule-stabilizing agent. The fluorescence staining of polarized cells indicated an increase in microtubule assembly accompanying disassembly of actin filaments. Furthermore, several actin-filament-disrupting agents, other than C 2 toxin, also induced microtubule assembly and cell polarization, irrespective of their different mechanisms of action. The effects induced by some of the agents, which have lower binding affinities for actin, were reversible in response to the re-assembly of actin filaments.Conclusions. Thus the disassembly of actin filaments by C 2 toxin and actin-filament-disrupting agents induces assembly of microtubules followed by polarization of human leukaemia cell lines, indicating that the assembly/disassembly equilibrium of actin filaments influences the dynamics of microtubules, which control cell morphology and, in turn, diverse cellular processes.

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Processes induced by tau expression in Sf9 cells have an axon-like microtubule organization.

Cited by 144 publications

References 52 publications

The tau proteins in neuronal growth and development

The tau proteins in neuronal growth and development

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

Disassembly of actin filaments by botulinum C₂ toxin and actin‐filament‐disrupting agents induces assembly of microtubules in human leukaemia cell lines

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Processes induced by tau expression in Sf9 cells have an axon-like microtubule organization.

Cited by 144 publications

References 52 publications

The tau proteins in neuronal growth and development

The tau proteins in neuronal growth and development

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

Disassembly of actin filaments by botulinum C2 toxin and actin‐filament‐disrupting agents induces assembly of microtubules in human leukaemia cell lines

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Disassembly of actin filaments by botulinum C₂ toxin and actin‐filament‐disrupting agents induces assembly of microtubules in human leukaemia cell lines