The AP-2 complex has a specialized clathrin-independent role in apical endocytosis and polar growth in fungi

  1. Olga Martzoukou
  2. Sotiris Amillis
  3. Amalia Zervakou
  4. Savvas Christoforidis
  5. George Diallinas  Is a corresponding author
  1. National and Kapodistrian University of Athens, Greece
  2. Foundation for Research and Technology, Greece

Abstract

Filamentous fungi provide excellent systems for investigating the role of the AP-2 complex in polar growth. Using Aspergillus nidulans, we show that AP-2 has a clathrin-independent essential role in polarity maintenance and growth. This is in line with a sequence analysis showing that the AP-2 β subunit (β2) of higher fungi lacks a clathrin-binding domain, and experiments showing that AP-2 does not co-localize with clathrin. We provide genetic and cellular evidence that AP-2 interacts with endocytic markers SlaBEnd4 and SagAEnd3 and the lipid flippases DnfA and DnfB in the sub-apical collar region of hyphae. The role of AP-2 in the maintenance of proper apical membrane lipid and cell wall composition is further supported by its functional interaction with BasA (sphingolipid biosynthesis) and StoA (apical sterol-rich membrane domains), and its essentiality in polar deposition of chitin. Our findings support that the AP-2 complex of dikarya has acquired, in the course of evolution, a specialized clathrin-independent function necessary for fungal polar growth.

Article and author information

Author details

  1. Olga Martzoukou

    Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
    Competing interests
    The authors declare that no competing interests exist.
  2. Sotiris Amillis

    Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
    Competing interests
    The authors declare that no competing interests exist.
  3. Amalia Zervakou

    Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
    Competing interests
    The authors declare that no competing interests exist.
  4. Savvas Christoforidis

    Institute of Molecular Biology and Biotechnology-Biomedical Research, Foundation for Research and Technology, Ioannina, Greece
    Competing interests
    The authors declare that no competing interests exist.
  5. George Diallinas

    Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
    For correspondence
    diallina@biol.uoa.gr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3426-726X

Funding

Fondation Sante

  • George Diallinas

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

Reviewing Editor

  1. Randy Schekman, Howard Hughes Medical Institute, University of California, Berkeley, United States

Publication history

  1. Received: July 27, 2016
  2. Accepted: February 7, 2017
  3. Accepted Manuscript published: February 21, 2017 (version 1)
  4. Version of Record published: March 6, 2017 (version 2)

Copyright

© 2017, Martzoukou 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.

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  1. Olga Martzoukou
  2. Sotiris Amillis
  3. Amalia Zervakou
  4. Savvas Christoforidis
  5. George Diallinas
(2017)
The AP-2 complex has a specialized clathrin-independent role in apical endocytosis and polar growth in fungi
eLife 6:e20083.
https://doi.org/10.7554/eLife.20083

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