Microtubules provide directional cues for polarized axonal transport through interaction with kinesin motor head

Nakata, Takao; Hirokawa, Nobutaka

doi:10.1083/jcb.200302175

Cited by 299 publications

(351 citation statements)

References 37 publications

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“…This stabilization probably reflects association along the AIS MT lattice rather than a dynamic accumulation of MT plus-ends, as indicated by the FRAP and MT perturbation experiments. This result is consistent with the findings of Nakata et al (25) showing that transfected EB1-GFP can bind along the MT lattice in the AIS. Second, the ankG-binding site on EB3 also is used by EB proteinbinding +TIPs, and the absence of +TIP partners in the AIS suggests that they could be excluded by ankG binding to EB proteins.…”

Section: Discussionsupporting

confidence: 83%

End-binding proteins EB3 and EB1 link microtubules to ankyrin G in the axon initial segment

Leterrier

Vacher

Fache

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

148

152

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The axon initial segment (AIS) plays a key role in maintaining the molecular and functional polarity of the neuron. The relationship between the AIS architecture and the microtubules (MTs) supporting axonal transport is unknown. Here we provide evidence that the MT plus-end-binding (EB) proteins EB1 and EB3 have a role in the AIS in addition to their MT plus-end tracking protein behavior in other neuronal compartments. In mature neurons, EB3 is concentrated and stabilized in the AIS. We identified a direct interaction between EB3/EB1 and the AIS scaffold protein ankyrin G (ankG). In addition, EB3 and EB1 participate in AIS maintenance, and AIS disassembly through ankG knockdown leads to cell-wide up-regulation of EB3 and EB1 comets. Thus, EB3 and EB1 coordinate a molecular and functional interplay between ankG and the AIS MTs that supports the central role of ankG in the maintenance of neuronal polarity. N eurons are highly polarized cells that rely on microtubules (MTs) for maintenance of their architecture and long-range polarized trafficking (1). MTs supporting axonal transport travel through the axon initial segment (AIS), a compartment that is essential for the generation of action potentials (2) and the maintenance of neuronal polarity (3). Generation of action potentials depends on the concentration of voltage-gated sodium (Nav) and potassium channels at the AIS, which are tethered at the plasma membrane via their interaction with ankyrin G (ankG (4-7). ankG, in turn, is linked to the actin cytoskeleton via βIV-spectrin and organizes AIS formation by recruiting membrane proteins and βIV-spectrin to the nascent AIS (3).The AIS maintains neuronal polarity by forming a diffusion barrier for membrane constituents at the cell surface (4,8,9) and also by dampening intracellular diffusion and vesicular transport through the AIS (10). Both phenomena depend on ankG, because depletion of ankG results in the disappearance of AIS and the acquisition of dendritic identity by the proximal axon (11,12). However, the molecular role of ankG in the intracellular AIS organization is still unknown. The dependence of the AIS intracellular filter on ankG (10) and the disorganization of MT bundles in the AIS of Purkinje cells from ankG-deficient mice (12) suggest an unknown link between ankG and MTs in the AIS.The end-binding (EB) proteins family, composed of three members (EB1-3), has been described as plus-end-tracking proteins (+TIPs) that coordinate a network of dynamic proteins on the growing MT plus-ends (13). In neurons, EB1 has been implicated in axonal transport (14, 15), whereas EB3 has been characterized as a molecular link between MTs and the actin cytoskeleton (16, 17). We hypothesized that EB proteins could have a role in the AIS via interaction with the ankG/βIV-spectrin scaffold. We first found that EB3 is accumulated and stabilized in the AIS of mature neurons. Both EB3 and EB1 bind to ankG and participate in the maintenance of the AIS scaffold. Reciprocally, altering neuronal polarity through ankG knockdown in...

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Section: Discussionsupporting

confidence: 83%

End-binding proteins EB3 and EB1 link microtubules to ankyrin G in the axon initial segment

Leterrier

Vacher

Fache

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

148

152

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“…Disruption of axonal transport can lead to neuronal cell death in mice (LaMonte et al, 2002) and Drosophila (Gunawardena and Goldstein, 2001;Gunawardena et al, 2003). Although the underlying mechanism connecting microtubule dynamics to axonal transport is unclear, low concentrations of taxol have been shown to compromise axonal transport (Nakata and Hirokawa, 2003). At the same time, other work suggests that increased levels of tau may interfere with axonal transport via a competition between tau and motor proteins (Trinczek et al, 1999;Stamer et al, 2002;Mandelkow et al, 2003).…”

Section: How Might Tau Dysfunction Cause Neurodegeneration?mentioning

confidence: 99%

Modulation of Microtubule Dynamics by Tau in Living Cells: Implications for Development and Neurodegeneration

Bunker

Wilson

Jordan

et al. 2004

MBoC

134

127

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The neural microtubule-associated protein tau binds to and stabilizes microtubules. Because of alternative mRNA splicing, tau is expressed with either 3 or 4 C-terminal repeats. Two observations indicate that differences between these tau isoforms are functionally important. First, the pattern of tau isoform expression is tightly regulated during development. Second, mutation-induced changes in tau RNA splicing cause neuronal cell death and dementia simply by altering the isoform expression ratio. To investigate whether 3-and 4-repeat tau differentially regulate microtubule behavior in cells, we microinjected physiological levels of these two isoforms into EGFP-tubulin-expressing cultured MCF7 cells and measured the effects on the dynamic instability behavior of individual microtubules by time-lapse microscopy. Both isoforms suppressed microtubule dynamics, though to different extents. Specifically, 4-repeat tau reduced the rate and extent of both growing and shortening events. In contrast, 3-repeat tau stabilized most dynamic parameters about threefold less potently than 4-repeat tau and had only a minimal ability to suppress shortening events. These differences provide a mechanistic rationale for the developmental shift in tau isoform expression and are consistent with a loss-of-function model in which abnormal tau isoform expression results in the inability to properly regulate microtubule dynamics, leading to neuronal cell death and dementia. INTRODUCTIONThe microtubule-associated protein tau promotes neuronal cell polarization and axonal outgrowth; it is also necessary for maintaining axonal morphology and axonal transport (Caceres and Kosik, 1990;Esmaeli-Azad et al., 1994;Trinczek et al., 1999;Stamer et al., 2002). Alternatively, abnormal tau is the major component of neurofibrillary tangles, hallmark pathological features of Alzheimer's disease and related dementias.Mechanistically, tau acts by binding to microtubules directly and regulating their growing, shortening, and treadmilling dynamics (Drechsel et al., 1992;Panda et al., 1995Panda et al., , 1999Trinczek et al., 1995). Because tight regulation of microtubule dynamics and microtubule behavior can be critical to cell viability (Jordan et al., 1996;Goncalves et al., 2001), fine regulation of tau activity may be equally critical.Tau activity is regulated in part by alternative mRNA splicing, which leads to the expression of two families of tau isoforms, those containing four C-terminal repeats and those with three such repeats ( Figure 1A; Lee et al., 1988;Himmler, 1989). In vitro studies have shown that 4-repeat tau binds to, assembles, and stabilizes microtubules more effectively than 3-repeat tau (Butner and Kirschner, 1991;Gustke et al., 1994;Trinczek et al., 1995;Goode et al., 2000;Panda et al., 2003). However, there are limited data assessing the abilities of 3-or 4-repeat tau to modulate dynamics in a complex cellular environment.The importance of functional differences between 3-and 4-repeat tau is highlighted by two observations. First, altho...

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“…The question arises how the viral components, consisting of a relatively limited variety of types, in the more distal axon are segregated from the multiple forms found in the neuron cell body. An axon-specific mechanism, such as restricted localization of a specific kinesin or kinesin-related protein, might limit transport of capsid to the cell body and proximal axon (Klopfenstein et al, 2000;Nakata and Hirokawa, 2003;Hirokawa and Takemura, 2005). The high density of microtubules in the initial segment and their propensity to bind to particular motor molecules also has been proposed as a potential "fence" to sort motor molecules and secondarily axonally transported elements from the pre-transport population (Nakata and Hirokawa, 2003).…”

Section: How Viral Dna Is Axonally Transportedmentioning

confidence: 99%

“…An axon-specific mechanism, such as restricted localization of a specific kinesin or kinesin-related protein, might limit transport of capsid to the cell body and proximal axon (Klopfenstein et al, 2000;Nakata and Hirokawa, 2003;Hirokawa and Takemura, 2005). The high density of microtubules in the initial segment and their propensity to bind to particular motor molecules also has been proposed as a potential "fence" to sort motor molecules and secondarily axonally transported elements from the pre-transport population (Nakata and Hirokawa, 2003). However, it is unlikely that the initial segment is the precise site of nucleocapsid segregation, since a mixed population of viral structures, including nucleocapsids, can be found immediately beyond the initial segment (Fig.…”

Section: How Viral Dna Is Axonally Transportedmentioning

confidence: 99%

Viral regulation of the long distance axonal transport of herpes simplex virus nucleocapsid

et al. 2007

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Abstract-Many membranous organelles and protein complexes are normally transported anterograde within axons to the presynaptic terminal, and details of the motors, adaptors and cargoes have received significant attention. Much less is known about the transport in neurons of non-membrane bound particles, such as mRNAs and their associated proteins. We propose that herpes simplex virus type 1 (HSV) can be used to study the detailed mechanisms regulating long distance transport of particles in axons. A critical step in the transmission of HSV from one infected neuron to the next is the polarized anterograde axonal transport of viral DNA from the host infected nerve cell body to the axon terminal. Using the in vivo mouse retinal ganglion cell model infected with wild type virus or a mutant strain that lacks the protein Us9, we found that Us9 protein was necessary for long distance anterograde axonal transport of viral nucleocapsid (DNA surrounded by capsid proteins), but unnecessary for transport of virus envelope. Thus, we conclude that nucleocapsid can be transported independently down axons via a Us9-dependent mechanism.

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Microtubules provide directional cues for polarized axonal transport through interaction with kinesin motor head

Cited by 299 publications

References 37 publications

End-binding proteins EB3 and EB1 link microtubules to ankyrin G in the axon initial segment

End-binding proteins EB3 and EB1 link microtubules to ankyrin G in the axon initial segment

Modulation of Microtubule Dynamics by Tau in Living Cells: Implications for Development and Neurodegeneration

Viral regulation of the long distance axonal transport of herpes simplex virus nucleocapsid

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