Keratins and Plakin family cytolinker proteins control the length of epithelial microridge protrusions

  1. Yasuko Inaba  Is a corresponding author
  2. Vasudha Chauhan
  3. Aaron Paul van Loon
  4. Lamia Saiyara Choudhury
  5. Alvaro Sagasti  Is a corresponding author
  1. University of California, Los Angeles, United States

Abstract

Actin filaments and microtubules create diverse cellular protrusions, but intermediate filaments, the strongest and most stable cytoskeletal elements, are not known to directly participate in the formation of protrusions. Here we show that keratin intermediate filaments directly regulate the morphogenesis of microridges, elongated protrusions arranged in elaborate maze-like patterns on the surface of mucosal epithelial cells. We found that microridges on zebrafish skin cells contained both actin and keratin filaments. Keratin filaments stabilized microridges, and overexpressing keratins lengthened them. Envoplakin and Periplakin, Plakin family cytolinkers that bind F-actin and keratins, localized to microridges and were required for their morphogenesis. Strikingly, Plakin protein levels directly dictated microridge length. An actin-binding domain of Periplakin was required to initiate microridge morphogenesis, whereas Periplakin-keratin binding was required to elongate microridges. These findings separate microridge morphogenesis into distinct steps, expand our understanding of intermediate filament functions, and identify microridges as protrusions that integrate actin and intermediate filaments.

Data availability

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

Article and author information

Author details

  1. Yasuko Inaba

    Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
    For correspondence
    yasuko.nam@gmail.com
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3239-2075
  2. Vasudha Chauhan

    Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Aaron Paul van Loon

    Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Lamia Saiyara Choudhury

    Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Alvaro Sagasti

    Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
    For correspondence
    sagasti@mcdb.ucla.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6823-0692

Funding

NIGMS (R01GM122901)

  • Alvaro Sagasti

NEI (R21EY024400)

  • Alvaro Sagasti

NIGMS (GM007185)

  • Aaron Paul van Loon

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

Reviewing Editor

  1. Michel Bagnat, Duke University, United States

Ethics

Animal experimentation: All animal experimental procedures were approved by the Chancellor's Animal Research Care Committee at UCLA (protocol #2005-117-41D).

Version history

  1. Received: April 22, 2020
  2. Accepted: September 4, 2020
  3. Accepted Manuscript published: September 7, 2020 (version 1)
  4. Version of Record published: October 5, 2020 (version 2)
  5. Version of Record updated: October 6, 2020 (version 3)

Copyright

© 2020, Inaba 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

  • 2,094
    views
  • 286
    downloads
  • 20
    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. Yasuko Inaba
  2. Vasudha Chauhan
  3. Aaron Paul van Loon
  4. Lamia Saiyara Choudhury
  5. Alvaro Sagasti
(2020)
Keratins and Plakin family cytolinker proteins control the length of epithelial microridge protrusions
eLife 9:e58149.
https://doi.org/10.7554/eLife.58149

Share this article

https://doi.org/10.7554/eLife.58149

Further reading

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Jiabin Pan, Rui Zhou ... Xiang-dong Li
    Research Article

    Transport and localization of melanosome at the periphery region of melanocyte are depended on myosin-5a (Myo5a), which associates with melanosome by interacting with its adaptor protein melanophilin (Mlph). Mlph contains four functional regions, including Rab27a-binding domain, Myo5a GTD-binding motif (GTBM), Myo5a exon F-binding domain (EFBD), and actin-binding domain (ABD). The association of Myo5a with Mlph is known to be mediated by two specific interactions: the interaction between the exon-F-encoded region of Myo5a and Mlph-EFBD and that between Myo5a-GTD and Mlph-GTBM. Here, we identify a third interaction between Myo5a and Mlph, that is, the interaction between the exon-G-encoded region of Myo5a and Mlph-ABD. The exon-G/ABD interaction is independent from the exon-F/EFBD interaction and is required for the association of Myo5a with melanosome. Moreover, we demonstrate that Mlph-ABD interacts with either the exon-G or actin filament, but cannot interact with both of them simultaneously. Based on above findings, we propose a new model for the Mlph-mediated Myo5a transportation of melanosomes.

    1. Cell Biology
    Yuhao Wang, Linhao Ruan ... Rong Li
    Research Article

    Mitochondria are the cellular energy hub and central target of metabolic regulation. Mitochondria also facilitate proteostasis through pathways such as the ‘mitochondria as guardian in cytosol’ (MAGIC) whereby cytosolic misfolded proteins (MPs) are imported into and degraded inside mitochondria. In this study, a genome-wide screen in Saccharomyces cerevisiae uncovered that Snf1, the yeast AMP-activated protein kinase (AMPK), inhibits the import of MPs into mitochondria while promoting mitochondrial biogenesis under glucose starvation. We show that this inhibition requires a downstream transcription factor regulating mitochondrial gene expression and is likely to be conferred through substrate competition and mitochondrial import channel selectivity. We further show that Snf1/AMPK activation protects mitochondrial fitness in yeast and human cells under stress induced by MPs such as those associated with neurodegenerative diseases.