Kiaa1024L/Minar2 is essential for hearing by regulating cholesterol distribution in hair bundles

Abstract

Unbiased genetic screens implicated a number of uncharacterized genes in hearing loss, suggesting some biological processes required for auditory function remain unexplored. Loss of Kiaa1024L/Minar2, a previously understudied gene, caused deafness in mice, but how it functioned in the hearing was unclear. Here we show that disruption of kiaa1024L/minar2 causes hearing loss in the zebrafish. Defects in mechanotransduction, longer and thinner hair bundles, and enlarged apical lysosomes in hair cells are observed in kiaa1024L/minar2 mutant. In cultured cells, Kiaa1024L/Minar2 is mainly localized to lysosomes and its overexpression recruits cholesterol and increases cholesterol labeling. Strikingly, cholesterol is highly enriched in the hair bundle membrane, and loss of kiaa1024L/minar2 reduces cholesterol localization to the hair bundles. Lowering cholesterol levels aggravates, while increasing cholesterol levels rescues hair cell defects in kiaa1024L/minar2 mutant. Therefore cholesterol plays an essential role in hair bundles, and Kiaa1024L/Minar2 regulates cholesterol distribution and homeostasis to ensure normal hearing.

Data availability

All data generated or analyzed during this study are included in the manuscript and supporting files. Source Data files have been provided.

Article and author information

Author details

  1. Ge Gao

    Institutes of Brain Science, Fudan University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  2. Shuyu Guo

    Institutes of Brain Science, Fudan University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  3. Quan Zhang

    Institutes of Brain Science, Fudan University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  4. Hefei Zhang

    Institutes of Brain Science, Fudan University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  5. Cuizhen Zhang

    Institutes of Brain Science, Fudan University, Shanghai, China
    Competing interests
    The authors declare that no competing interests exist.
  6. Gang Peng

    Institute of Brain Science, Fudan University, Shanghai, China
    For correspondence
    gangpeng@fudan.edu.cn
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6625-5426

Funding

National Key Research and Development Program of China (2018YFA0801000)

  • Gang Peng

National Natural Science Foundation of China (31571067)

  • Gang Peng

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

Ethics

Animal experimentation: The animal use protocols were approved by the Fudan University Shanghai Medical College Institution Animal Care and Use Committee (130227-092, 150119-088 and 190221-147). All animals were handled in accordance with the Fudan University Regulations on Animal Experiments.

Copyright

© 2022, Gao 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

  • 1,102
    views
  • 235
    downloads
  • 4
    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. Ge Gao
  2. Shuyu Guo
  3. Quan Zhang
  4. Hefei Zhang
  5. Cuizhen Zhang
  6. Gang Peng
(2022)
Kiaa1024L/Minar2 is essential for hearing by regulating cholesterol distribution in hair bundles
eLife 11:e80865.
https://doi.org/10.7554/eLife.80865

Share this article

https://doi.org/10.7554/eLife.80865

Further reading

    1. Cell Biology
    Jeongsik Kim, Dahyun Kim ... Dae-Sik Lim
    Research Article

    Cell survival in metazoans depends on cell attachment to the extracellular matrix (ECM) or to neighboring cells. Loss of such attachment triggers a type of programmed cell death known as anoikis, the acquisition of resistance to which is a key step in cancer development. The mechanisms underlying anoikis resistance remain unclear, however. The intracellular F-actin cytoskeleton plays a key role in sensing the loss of cell–ECM attachment, but how its disruption affects cell fate during such stress is not well understood. Here, we reveal a cell survival strategy characterized by the formation of a giant unilocular vacuole (GUVac) in the cytoplasm of the cells whose actin cytoskeleton is disrupted during loss of matrix attachment. Time-lapse imaging and electron microscopy showed that large vacuoles with a diameter of >500 nm accumulated early after inhibition of actin polymerization in cells in suspension culture, and that these vacuoles subsequently coalesced to form a GUVac. GUVac formation was found to result from a variation of a macropinocytosis-like process, characterized by the presence of inwardly curved membrane invaginations. This phenomenon relies on both F-actin depolymerization and the recruitment of septin proteins for micron-sized plasma membrane invagination. The vacuole fusion step during GUVac formation requires PI(3)P produced by VPS34 and PI3K-C2α on the surface of vacuoles. Furthermore, its induction after loss of matrix attachment conferred anoikis resistance. Our results thus show that the formation of a previously unrecognized organelle promotes cell survival in the face of altered actin and matrix environments.

    1. Cell Biology
    2. Plant Biology
    Masanori Izumi, Sakuya Nakamura ... Shinya Hagihara
    Research Article

    Plants distribute many nutrients to chloroplasts during leaf development and maturation. When leaves senesce or experience sugar starvation, the autophagy machinery degrades chloroplast proteins to facilitate efficient nutrient reuse. Here, we report on the intracellular dynamics of an autophagy pathway responsible for piecemeal degradation of chloroplast components. Through live-cell monitoring of chloroplast morphology, we observed the formation of chloroplast budding structures in sugar-starved leaves. These buds were then released and incorporated into the vacuolar lumen as an autophagic cargo termed a Rubisco-containing body. The budding structures did not accumulate in mutants of core autophagy machinery, suggesting that autophagosome creation is required for forming chloroplast buds. Simultaneous tracking of chloroplast morphology and autophagosome development revealed that the isolation membranes of autophagosomes interact closely with part of the chloroplast surface before forming chloroplast buds. Chloroplasts then protrude at the site associated with the isolation membranes, which divide synchronously with autophagosome maturation. This autophagy-related division does not require DYNAMIN-RELATED PROTEIN 5B, which constitutes the division ring for chloroplast proliferation in growing leaves. An unidentified division machinery may thus fragment chloroplasts for degradation in coordination with the development of the chloroplast-associated isolation membrane.