Article

CRL4ACRBN E3 ubiquitin ligase restricts BK channel activity and prevents epileptogenesis

  • Nature Communications 5, Article number: 3924 (2014)
  • doi:10.1038/ncomms4924
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Abstract

Ion channels regulate membrane excitation, and mutations of ion channels often cause serious neurological disorders including epilepsy. Compared with extensive analyses of channel protein structure and function, much less is known about the fine tuning of channel activity by post-translational modification. Here we report that the large conductance, Ca2+- and voltage-activated K+ (BK) channels are targeted by the E3 ubiquitin ligase CRL4ACRBN for polyubiquitination and retained in the endoplasmic reticulum (ER). Inactivation of CRL4ACRBN releases deubiquitinated BK channels from the ER to the plasma membrane, leading to markedly enhanced channel activity. Mice with CRL4ACRBN mutation in the brain or treated with a CRL4ACRBN inhibitor are very sensitive to seizure induction, which can be attenuated by blocking BK channels. Finally, the mutant mice develop spontaneous epilepsy when aged. Therefore, ubiquitination of BK channels before their cell surface expression is an important step to prevent systemic neuronal excitability and epileptogenesis.

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Acknowledgements

We thank Z. Ronai, X.H. Feng and K.L. Guan for comments and discussion, C. Schweizer for Camk2a-Cre transgenic mouse, X.H. Feng. Z.P. Xia, M.J. Shipton and T. Ito for expression vectors, S. Ye for the Slo1 cDNA construct, and W. Yang and X.Y. Yan for technical assistance. This work was supported in part by funds from the Zhejiang Provincial Outstanding Young Investigator Award (R3110131), Fundamental Research Funds for the Central Universities and Key Construction Program of the National ‘985’ Project.

Author information

Affiliations

  1. Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China

    • Jiye Liu
    • , Xiaolong Zou
    • , Yan Feng
    • , Xianxian Zou
    •  & Yong Cang
  2. School of Medicine, Zhejiang University, Hangzhou, Zhejiang 310058, China

    • Jia Ye
    • , Zhenghao Xu
    • , Zhong Chen
    • , Yuezhou Li
    •  & Yong Cang

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Contributions

J.L. and Y.C. designed the study. J.L., Xiaolong Z. and Y.F. performed all the experiments except the patch clamp assays contributed by J.Y. and EEG recordings by Z.X., J.L., Y.L., Z.C. and Y.C. performed data analysis. Xianxian Z. was involved in project management. J.L. and Y.C. wrote the paper.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to Yong Cang.

Supplementary information

PDF files

  1. 1.

    Supplementary Figures

    Supplementary Figures 1-11

Videos

  1. 1.

    Supplementary Movie 1

    Time-lapse fluorescent microcopy imaging showing time-dependent accumulation of BK channels at cell surface after inhibition of CRL4ACRBN activity by MLN4924.

  2. 2.

    Supplementary Movie 2

    Video showing a DDB1F/F;Camk2α-Cre mouse (on the left side of the cage) being more susceptible to epilepsy induction than a wild type control.

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