Kinesin I Transports Tetramerized Kv3 Channels through the Axon Initial Segment via Direct Binding

Xu, Mingxuan; Gu, Yuanzheng; Barry, Joshua; Gu, Chen

doi:10.1523/jneurosci.3565-10.2010

Cited by 48 publications

(96 citation statements)

References 70 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A corollary to this is that specific classes of neurons might be particularly sensitive to such vesicle transport defects, similar to what is seen for GABAergic neurons in the KIF5A mutants (26). Intriguingly, sodium and potassium channel-containing vesicles have been shown to be transported in axons by Kinesin-1 (34,35), which is the Kinesin that we have focused on in this study, raising the possibility that transport defects of such channels might underlie the seizure phenotype in the pk sple /+ mutant. These channels associate directly with Khc (34, 35), yet we are able to suppress the seizure phenotype by reducing the dose of either Klc or Khc; collectively, these data suggest that Klc might be working together with Khc to modulate channel binding or transport, and that lowering the dose of either Kinesin component suppresses the aberrant transport of the channels.…”

Section: Discussionmentioning

confidence: 64%

prickle modulates microtubule polarity and axonal transport to ameliorate seizures in flies

Ehaideb

Iyengar

Ueda³

et al. 2014

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

View full text Add to dashboard Cite

Recent analyses in flies, mice, zebrafish, and humans showed that mutations in prickle orthologs result in epileptic phenotypes, although the mechanism responsible for generating the seizures was unknown. Here, we show that Prickle organizes microtubule polarity and affects their growth dynamics in axons of Drosophila neurons, which in turn influences both anterograde and retrograde vesicle transport. We also show that enhancement of the anterograde transport mechanism is the cause of the seizure phenotype in flies, which can be suppressed by reducing the level of either of two Kinesin motor proteins responsible for anterograde vesicle transport. Additionally, we show that seizure-prone prickle mutant flies have electrophysiological defects similar to other fly mutants used to study seizures, and that merely altering the balance of the two adult prickle isoforms in neurons can predispose flies to seizures. These data reveal a previously unidentified pathway in the pathophysiology of seizure disorders and provide evidence for a more generalized cellular mechanism whereby Prickle mediates polarity by influencing microtubule-mediated transport.epilepsy | planar cell polarity | spiny-legs | EB1-GFP | neurodegeneration E pilepsy, which affects ∼1% of the population, is a disabling and debilitating disease characterized by recurrent seizures. Coupling genetic analysis of human epilepsy cases with functional validation in animal models, we previously showed that mutations in human PRICKLE1 and PRICKLE2, as well as mutations in mouse, zebrafish and fly prickle (pk) orthologs, increase susceptibility to seizures (1-3). We recently showed that both mouse and fly Prickle can associate with Synapsin (4). However, little is known regarding what cellular process connects Prickle with epilepsy. Products of the prickle gene work in concert with a group of cytoplasmic and membrane-associated proteins including Frizzled (Fz) and Dishevelled (Dsh) to establish polarity of structures such as hairs and bristles in the fly epidermis (5-8). The fly pk locus expresses three alternately spliced isoforms, two of which, pk sple (prickle-spiny-legs) and pk pk (prickle-prickle), are expressed in postembryonic animals (5, 7). Homozygous pk pk and pk sple fly mutants show strong planar cell polarity (PCP) phenotypes in the wing and in the legs, respectively, in addition to other regions of the adult body (6, 7). Prickle (Pk) protein isoforms are localized to the proximal end of fly wing cells, whereas Fz and Dsh are localized distally (8).Here, we show that vesicle transport dynamics are altered in neurons of Drosophila mutant for either adult isoform of prickle. Seizure-prone pk sple heterozygotes show enhanced vesicle transport (along with electrophysiological defects similar to other seizure-prone mutant flies), and the seizure phenotypes can be rescued by lowering the dose of vesicle transport motor proteins. However, pk pk heterozygotes show severely reduced vesicle transport, with loss of both copies of pk pk showing a marked decrease i...

show abstract

Section: Discussionmentioning

confidence: 64%

prickle modulates microtubule polarity and axonal transport to ameliorate seizures in flies

Ehaideb

Iyengar

Ueda³

et al. 2014

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

View full text Add to dashboard Cite

show abstract

“…The AIS is not just a physical barrier that screens a molecule by its size, but a highly flexible structure that is capable of selecting specific molecular components. For example, the axonal entry of 70 kDa dextrans was prevented by AIS (Song et al, 2009), but the large 360 kDa K v 3.1b tetramer that interacts with ankyrin-G could pass through the AIS (Xu et al, 2010). Therefore, axonal transport of a molecule requires not only a molecular motor (kinesin or myosin) but also interaction of motor-cargo complex with AIS components, which allows the complex to pass through the AIS.…”

Section: Discussionmentioning

confidence: 99%

KIF21A-Mediated Axonal Transport and Selective Endocytosis Underlie the Polarized Targeting of NCKX2

Lee¹,

Lee²,

Lee³

et al. 2012

J. Neurosci.

View full text Add to dashboard Cite

We have previously shown that K ϩ -dependent Na ϩ /Ca 2ϩ exchanger (NCKX) is a major calcium clearance mechanism at the large axon terminals of central neurons, whereas their somata display little NCKX activity. We investigated mechanisms underlying the axonal polarization of NCKX2 in rat hippocampal neurons. We identified NCKX2 as the first neuron-specific cargo molecule of kinesin family member 21A (KIF21A). The intracellular loop of NCKX2 specifically interacted with the WD-40 repeats, a putative cargo-binding domain, of KIF21A. Dominant-negative mutant or depletion of KIF21A inhibited the transport of NCKX2-GFP to axon fibers. Knockdown of KIF21A caused calcium dysregulation at axonal boutons but not at somatodendritic regions. Despite the axonal polarization of the NCKX activity, both somatodendritic and axonal regions were immunoreactive to NCKX2. The surface expression of NCKX2 revealed by live-cell immunocytochemistry, however, displayed highly polarized distribution to the axon. Inhibition of endocytosis increased the somatodendritic surface NCKX2 and thus abolished the axonal polarization of surface NCKX2. These results indicate that KIF21A-mediated axonal transport and selective somatodendritic endocytosis underlie the axonal polarized surface expression of NCKX2.

show abstract

“…Whole-cell Patch Clamp Recording-The experimental procedure of whole-cell recording of HEK293 cells expressing Kv channel constructs was described previously (5). Transfected HEK293 cells were identified by fluorescence from cotransfected YFP or mCherry inserted into the N-terminal region of TAG-1 and recorded in Hanks' buffer (150 mM NaCl, 4 mM KCl, 1.2 mM MgCl 2 , 10 mg/ml glucose, 1 mM CaCl 2 , 20 mM HEPES, pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

“…Molecular mechanisms underlying polarized axon-dendrite targeting of Kv channels have been extensively studied (1)(2)(3)(4)(5)(6)(7)(8)(9)(10). In contrast, channel targeting in distinct membrane domains within axons is much less understood.…”

mentioning

confidence: 99%

Clustering and Activity Tuning of Kv1 Channels in Myelinated Hippocampal Axons

2011

Journal of Biological Chemistry

View full text Add to dashboard Cite

Precise localization of axonal ion channels is crucial for proper electrical and chemical functions of axons. In myelinated axons, Kv1 (Shaker) voltage-gated potassium (Kv) channels are clustered in the juxtaparanodal regions flanking the node of Ranvier. The clustering can be disrupted by deletion of various proteins in mice, including contactin-associated protein-like 2 (Caspr2) and transient axonal glycoprotein-1 (TAG-1), a glycosylphosphatidylinositol-anchored cell adhesion molecule. However, the mechanism and function of Kv1 juxtaparanodal clustering remain unclear. Here, using a new myelin coculture of hippocampal neurons and oligodendrocytes, we report that tyrosine phosphorylation plays a critical role in TAG-1-mediated clustering of axonal Kv1.2 channels. In the coculture, myelin specifically ensheathed axons but not dendrites of hippocampal neurons and clustered endogenous axonal Kv1.2 into internodes. The trans-homophilic interaction of TAG-1 was sufficient to position Kv1.2 clusters on axonal membranes in a neuron/HEK293 coculture. Mutating a tyrosine residue (Tyr 458 ) in the Kv1.2 C terminus or blocking tyrosine phosphorylation disrupted myelin-and TAG-1-mediated clustering of axonal Kv1.2. Furthermore, Kv1.2 voltage dependence and activation threshold were reduced by TAG-1 coexpression. This effect was eliminated by the Tyr 458 mutation or by cholesterol depletion. Taken together, our studies suggest that myelin regulates both trafficking and activity of Kv1 channels along hippocampal axons through TAG-1. Proper subcellular targeting of various Kv channels2 is critical for neuronal excitability and synaptic transmission. Molecular mechanisms underlying polarized axon-dendrite targeting of Kv channels have been extensively studied (1-10). In contrast, channel targeting in distinct membrane domains within axons is much less understood. Most axons in mammals are wrapped by layers of compact lipid membranes from myelinating glial cells, oligodendrocytes in the central nervous system (CNS) and Schwann cells in the peripheral nervous system. Myelinated axons form distinct membrane domains, such as nodes of Ranvier, paranodes, and juxtaparanodal (JXP), and internodal regions (11)(12)(13)(14). In myelinated axons of both CNS and peripheral nervous system, Kv1 channels are clustered into JXP regions, controlling the fidelity of action potential conduction (11,(15)(16)(17).Based on the findings that the JXP targeting of Kv1 channels was largely eliminated in both Caspr2 (contactin-associated protein-like 2) and TAG-1 (transient axonal glycoprotein-1) knock-out mice, it was hypothesized that Caspr2 interacts with TAG-1 and clusters Kv1 channels via a PDZ domain-containing protein (18,19). Whereas Caspr2 is expressed only in neurons, TAG-1 is expressed in both neurons and myelinating glial cells (19 -21). Caspr2 has a PDZ domain ligand at its C terminus, but deleting PDZ domain-containing proteins, such as PSD-95 (postsynaptic density-95) and/or PSD-93 (postsynaptic density-93), in mice had no effect on the K...

show abstract

Kinesin I Transports Tetramerized Kv3 Channels through the Axon Initial Segment via Direct Binding

Abstract: Precise targeting of various voltage-gated ion channels to proper membrane domains is crucial for their distinct roles in neuronal

Cited by 48 publications

References 70 publications

prickle modulates microtubule polarity and axonal transport to ameliorate seizures in flies

prickle modulates microtubule polarity and axonal transport to ameliorate seizures in flies

KIF21A-Mediated Axonal Transport and Selective Endocytosis Underlie the Polarized Targeting of NCKX2

Clustering and Activity Tuning of Kv1 Channels in Myelinated Hippocampal Axons

Contact Info

Product

Resources

About