The role of Kif5B in axonal localization of Kv1 K+ channels

Authors

  • Jacqueline Rivera,

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    • *

      J.R. and P.-J.C. contributed equally to this work.

  • Po-Ju Chu,

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    • *

      J.R. and P.-J.C. contributed equally to this work.

    • Present Address: Department of Life Sciences, Chang Gung University, Kwei-Shan, Taoyuan, Taiwan, Republic of China.

  • Tommy L. Lewis Jr,

    1. University of Southern California, Department of Biological Sciences, Division of Molecular and Computational Biology, and Program in Neuroscience, 1050 Childs Way MCB 204, Los Angeles, CA 90089–2910, USA
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  • Don B. Arnold

    1. University of Southern California, Department of Biological Sciences, Division of Molecular and Computational Biology, and Program in Neuroscience, 1050 Childs Way MCB 204, Los Angeles, CA 90089–2910, USA
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Dr Don B. Arnold, as above.
E-mail: darnold@usc.edu

Abstract

Here we present evidence that the kinesin, Kif5B, is involved in the transportation and axonal targeting of Kv1 channels. We show that a dominant negative variant of Kif5B specifically blocks localization to the axon of expressed, tagged versions of Kv1.3 in cultured cortical slices. In addition, the dominant negative variant of Kif5B blocks axonal localization of endogenous Kv1.1, Kv1.2, and Kv1.4 in cortical neurons in dissociated cultures. We also found evidence that Kif5B interacts with Kv1 channels. Endogenous Kv1.2 colocalized with Kif5B in cortical neurons and coimmunoprecipitated with Kif5B from brain lysate. The T1 domain of Shaker K+ channels has been shown to play a critical role in targeting the channel to the axon. We have three pieces of evidence to suggest that the T1 domain also mediates interaction between Kv1 channels and Kif5B: Addition of the T1 domain to a heterologous protein, TfR, is sufficient to cause the resulting fusion protein, TfRT1, to colocalize with Kif5B. Also, the T1 domain is necessary for interaction of Kv1.3 with Kif5B in a coimmunoprecipitation assay. Finally, dominant negative variants of Kif5B block axonal targeting of TfRT1, but have no effect on dendritic localization of TfR. Together these data suggest a model where Kif5B interacts with Kv1 channels either directly or indirectly via the T1 domain, causing the channels to be transported to axons.

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