Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy

  1. Naonobu Fujita  Is a corresponding author
  2. Wilson Huang
  3. Tzu-han Lin
  4. Jean-Francois Groulx
  5. Steve Jean
  6. Yoshihiko Kuchitsu
  7. Ikuko Koyama-Honda
  8. Noboru Mizushima
  9. Mitsunori Fukuda
  10. Amy A Kiger  Is a corresponding author
  1. University of California, San Diego, United States
  2. Tohoku University, Japan
  3. The University of Tokyo, Japan

Abstract

Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power of contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite the ongoing muscle remodeling that occurs with muscle atrophy, damage and aging. We uncovered an essential role for autophagy in T-tubule remodeling with genetic screens of a developmentally regulated remodeling program in Drosophila abdominal muscles. Here, we show that autophagy is both upregulated with and required for progression through T-tubule disassembly stages. Along with known mediators of autophagosome-lysosome fusion, our screens uncovered an unexpected shared role for Rab2 with a broadly conserved function in autophagic clearance. Rab2 localizes to autophagosomes and binds to HOPS complex members, suggesting a direct role in autophagosome tethering/fusion. Together, the high membrane flux with muscle remodeling permits unprecedented analysis both of T-tubule dynamics and fundamental trafficking mechanisms.

Article and author information

Author details

  1. Naonobu Fujita

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    For correspondence
    naonobu.fujita.b8@tohoku.ac.jp
    Competing interests
    No competing interests declared.
  2. Wilson Huang

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    Competing interests
    No competing interests declared.
  3. Tzu-han Lin

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    Competing interests
    No competing interests declared.
  4. Jean-Francois Groulx

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    Competing interests
    No competing interests declared.
  5. Steve Jean

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    Competing interests
    No competing interests declared.
  6. Yoshihiko Kuchitsu

    Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
    Competing interests
    No competing interests declared.
  7. Ikuko Koyama-Honda

    Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
    Competing interests
    No competing interests declared.
  8. Noboru Mizushima

    Department of Biochemistry and Molecular Biology, Graduate School and Faculty of Medicine, The University of Tokyo, Tokyo, Japan
    Competing interests
    Noboru Mizushima, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6258-6444
  9. Mitsunori Fukuda

    Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Sendai, Japan
    Competing interests
    No competing interests declared.
  10. Amy A Kiger

    Section of Cell and Developmental Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, United States
    For correspondence
    akiger@ucsd.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4300-176X

Funding

American Heart Association (Innovative Research Grant,15IRG22830029)

  • Amy A Kiger

Japan Society for the Promotion of Science (Postdoctoral Fellowship)

  • Naonobu Fujita

Uehara Memorial Foundation (Postdoctoral Fellowship)

  • Naonobu Fujita

Kanae Foundation (Postdoctoral Fellowship)

  • Naonobu Fujita

Scientific Research on Innovative Areas (Grant-in-Aid for Scientific Research,25111005)

  • Noboru Mizushima

Ministry of Education, Culture, Sports, Science, and Technology (Grant-in-Aid for Scientific Research,16H01189)

  • Mitsunori Fukuda

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

Copyright

© 2017, Fujita 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

  • 5,931
    views
  • 1,213
    downloads
  • 99
    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. Naonobu Fujita
  2. Wilson Huang
  3. Tzu-han Lin
  4. Jean-Francois Groulx
  5. Steve Jean
  6. Yoshihiko Kuchitsu
  7. Ikuko Koyama-Honda
  8. Noboru Mizushima
  9. Mitsunori Fukuda
  10. Amy A Kiger
(2017)
Genetic screen in Drosophila muscle identifies autophagy-mediated T-tubule remodeling and a Rab2 role in autophagy
eLife 6:e23367.
https://doi.org/10.7554/eLife.23367

Share this article

https://doi.org/10.7554/eLife.23367

Further reading

    1. Cell Biology
    2. Developmental Biology
    Dilara N Anbarci, Jennifer McKey ... Blanche Capel
    Research Article

    The rete ovarii (RO) is an appendage of the ovary that has been given little attention. Although the RO appears in drawings of the ovary in early versions of Gray’s Anatomy, it disappeared from recent textbooks, and is often dismissed as a functionless vestige in the adult ovary. Using PAX8 immunostaining and confocal microscopy, we characterized the fetal development of the RO in the context of the mouse ovary. The RO consists of three distinct regions that persist in adult life, the intraovarian rete (IOR), the extraovarian rete (EOR), and the connecting rete (CR). While the cells of the IOR appear to form solid cords within the ovary, the EOR rapidly develops into a convoluted tubular epithelium ending in a distal dilated tip. Cells of the EOR are ciliated and exhibit cellular trafficking capabilities. The CR, connecting the EOR to the IOR, gradually acquires tubular epithelial characteristics by birth. Using microinjections into the distal dilated tip of the EOR, we found that luminal contents flow toward the ovary. Mass spectrometry revealed that the EOR lumen contains secreted proteins potentially important for ovarian function. We show that the cells of the EOR are closely associated with vasculature and macrophages, and are contacted by neuronal projections, consistent with a role as a sensory appendage of the ovary. The direct proximity of the RO to the ovary and its integration with the extraovarian landscape suggest that it plays an important role in ovary development and homeostasis.

    1. Cell Biology
    2. Developmental Biology
    Yan Zhang, Hua Zhang
    Insight

    Long thought to have little relevance to ovarian physiology, the rete ovarii may have a role in follicular dynamics and reproductive health.