The ESCRT Machinery regulates Retromer dependent Transcytosis of Septate Junction Components in Drosophila

  1. Hendrik Pannen
  2. Tim Rapp
  3. Thomas Klein  Is a corresponding author
  1. Heinrich-Heine-Universität Düsseldorf, Germany

Abstract

Loss of ESCRT function in Drosophila imaginal discs is known to cause neoplastic overgrowth fuelled by mis-regulation of signalling pathways. Its impact on junctional integrity, however, remains obscure. To dissect the events leading to neoplasia, we used transmission electron microscopy (TEM) on wing imaginal discs temporally depleted of the ESCRT-III core component Shrub. We find a specific requirement for Shrub in maintaining Septate Junction (SJ) integrity by transporting the Claudin Megatrachea (Mega) to the SJ. In absence of Shrub function, Mega is lost from the SJ and becomes trapped on endosomes coated with the endosomal retrieval machinery Retromer. We show that ESCRT function is required for apical localization and mobility of Retromer positive carrier vesicles, which mediate the biosynthetic delivery of Mega to the SJ. Accordingly, loss of Retromer function impairs the anterograde transport of several SJ core components, revealing a novel physiological role for this ancient endosomal agent.

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. Hendrik Pannen

    Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
    Competing interests
    The authors declare that no competing interests exist.
  2. Tim Rapp

    Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
    Competing interests
    The authors declare that no competing interests exist.
  3. Thomas Klein

    Institute of Genetics, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
    For correspondence
    thomas.klein@hhu.de
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2719-9617

Funding

Deutsche Forschungsgemeinschaft (Sachbeihilfe KL 1028/11-1)

  • Hendrik Pannen
  • Tim Rapp
  • Thomas Klein

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

Copyright

© 2020, Pannen 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

  • 1,879
    views
  • 208
    downloads
  • 12
    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. Hendrik Pannen
  2. Tim Rapp
  3. Thomas Klein
(2020)
The ESCRT Machinery regulates Retromer dependent Transcytosis of Septate Junction Components in Drosophila
eLife 9:e61866.
https://doi.org/10.7554/eLife.61866

Share this article

https://doi.org/10.7554/eLife.61866

Further reading

    1. Cancer Biology
    2. Cell Biology
    Rui Hua, Jean X Jiang
    Insight

    Cell crowding causes high-grade breast cancer cells to become more invasive by activating a molecular switch that causes the cells to shrink and spread.

    1. Cell Biology
    Dharmendra Kumar Nath, Subash Dhakal, Youngseok Lee
    Research Advance

    Understanding how the brain controls nutrient storage is pivotal. Transient receptor potential (TRP) channels are conserved from insects to humans. They serve in detecting environmental shifts and in acting as internal sensors. Previously, we demonstrated the role of TRPγ in nutrient-sensing behavior (Dhakal et al., 2022). Here, we found that a TRPγ mutant exhibited in Drosophila melanogaster is required for maintaining normal lipid and protein levels. In animals, lipogenesis and lipolysis control lipid levels in response to food availability. Lipids are mostly stored as triacylglycerol in the fat bodies (FBs) of D. melanogaster. Interestingly, trpγ deficient mutants exhibited elevated TAG levels and our genetic data indicated that Dh44 neurons are indispensable for normal lipid storage but not protein storage. The trpγ mutants also exhibited reduced starvation resistance, which was attributed to insufficient lipolysis in the FBs. This could be mitigated by administering lipase or metformin orally, indicating a potential treatment pathway. Gene expression analysis indicated that trpγ knockout downregulated brummer, a key lipolytic gene, resulting in chronic lipolytic deficits in the gut and other fat tissues. The study also highlighted the role of specific proteins, including neuropeptide DH44 and its receptor DH44R2 in lipid regulation. Our findings provide insight into the broader question of how the brain and gut regulate nutrient storage.