Abstract

ARL13B is a regulatory GTPase highly enriched in cilia. Complete loss of Arl13b disrupts cilia architecture, protein trafficking and Sonic hedgehog signaling. To determine whether ARL13B is required within cilia, we knocked in a cilia-excluded variant of ARL13B (V358A) and showed it retains all known biochemical function. We found that ARL13BV358A protein was expressed but could not be detected in cilia, even when retrograde ciliary transport was blocked. We showed Arl13bV358A/V358A mice are viable and fertile with normal Shh signal transduction. However, in contrast to wild type cilia, Arl13bV358A/V358A cells displayed short cilia and lacked ciliary ARL3 and INPP5E. These data indicate that ARL13B's role within cilia can be uncoupled from its function outside of cilia. Furthermore, these data imply that the cilia defects upon complete absence of ARL13B do not underlie the alterations in Shh transduction, which is unexpected given the requirement of cilia for Shh transduction.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Eduardo D Gigante

    Human Genetics, Emory University, Atlanta, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Megan R Taylor

    Human Genetics, Emory University, Atlanta, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Anna A Ivanova

    Biochemistry, Emory University, Atlanta, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Richard A Kahn

    Biochemistry, Emory University, Atlanta, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Tamara Caspary

    Human Genetics, Emory University, Atlanta, United States
    For correspondence
    tcaspar@emory.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6579-7589

Funding

NINDS (R01NS090029)

  • Tamara Caspary

NIGMS (R35GM122549)

  • Tamara Caspary

NIGMS (R35GM122568)

  • Richard A Kahn

NINDS (T32NS096050)

  • Eduardo D Gigante

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Jeremy F Reiter, University of California, San Francisco, United States

Ethics

Animal experimentation: All mice were cared for in accordance with NIH guidelines and Emory's Institutional Animal Care and Use Committee (IACUC) under protocols DAR-2003545-072919N and PROTO201700587.

Version history

  1. Received: July 23, 2019
  2. Accepted: February 25, 2020
  3. Accepted Manuscript published: March 4, 2020 (version 1)
  4. Version of Record published: March 16, 2020 (version 2)

Copyright

© 2020, Gigante et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

Metrics

  • 6,126
    views
  • 785
    downloads
  • 58
    citations

Views, downloads and citations are aggregated across all versions of this paper published by eLife.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Eduardo D Gigante
  2. Megan R Taylor
  3. Anna A Ivanova
  4. Richard A Kahn
  5. Tamara Caspary
(2020)
ARL13B regulates Sonic Hedgehog signaling from outside primary cilia
eLife 9:e50434.
https://doi.org/10.7554/eLife.50434

Share this article

https://doi.org/10.7554/eLife.50434

Further reading

    1. Cell Biology
    Makiko Kashio, Sandra Derouiche ... Makoto Tominaga
    Research Article

    Reports indicate that an interaction between TRPV4 and anoctamin 1 (ANO1) could be widely involved in water efflux of exocrine glands, suggesting that the interaction could play a role in perspiration. In secretory cells of sweat glands present in mouse foot pads, TRPV4 clearly colocalized with cytokeratin 8, ANO1, and aquaporin-5 (AQP5). Mouse sweat glands showed TRPV4-dependent cytosolic Ca2+ increases that were inhibited by menthol. Acetylcholine-stimulated sweating in foot pads was temperature-dependent in wild-type, but not in TRPV4-deficient mice and was inhibited by menthol both in wild-type and TRPM8KO mice. The basal sweating without acetylcholine stimulation was inhibited by an ANO1 inhibitor. Sweating could be important for maintaining friction forces in mouse foot pads, and this possibility is supported by the finding that wild-type mice climbed up a slippery slope more easily than TRPV4-deficient mice. Furthermore, TRPV4 expression was significantly higher in controls and normohidrotic skin from patients with acquired idiopathic generalized anhidrosis (AIGA) compared to anhidrotic skin from patients with AIGA. Collectively, TRPV4 is likely involved in temperature-dependent perspiration via interactions with ANO1, and TRPV4 itself or the TRPV4/ANO 1 complex would be targeted to develop agents that regulate perspiration.

    1. Cell Biology
    Yuki Date, Yukiko Sasazawa ... Shinji Saiki
    Research Article Updated

    The autophagy-lysosome pathway plays an indispensable role in the protein quality control by degrading abnormal organelles and proteins including α-synuclein (αSyn) associated with the pathogenesis of Parkinson’s disease (PD). However, the activation of this pathway is mainly by targeting lysosomal enzymic activity. Here, we focused on the autophagosome-lysosome fusion process around the microtubule-organizing center (MTOC) regulated by lysosomal positioning. Through high-throughput chemical screening, we identified 6 out of 1200 clinically approved drugs enabling the lysosomes to accumulate around the MTOC with autophagy flux enhancement. We further demonstrated that these compounds induce the lysosomal clustering through a JIP4-TRPML1-dependent mechanism. Among them, the lysosomal-clustering compound albendazole promoted the autophagy-dependent degradation of Triton-X-insoluble, proteasome inhibitor-induced aggregates. In a cellular PD model, albendazole boosted insoluble αSyn degradation. Our results revealed that lysosomal clustering can facilitate the breakdown of protein aggregates, suggesting that lysosome-clustering compounds may offer a promising therapeutic strategy against neurodegenerative diseases characterized by the presence of aggregate-prone proteins.