1. Plant Biology
Download icon

SUMOylation contributes to proteostasis of the chloroplast protein import receptor TOC159 during early development

  1. Sonia Accossato
  2. Felix Kessler  Is a corresponding author
  3. Venkatasalam Shanmugabalaji  Is a corresponding author
  1. Université de Neuchâtel, Switzerland
Short Report
  • Cited 0
  • Views 405
  • Annotations
Cite this article as: eLife 2020;9:e60968 doi: 10.7554/eLife.60968

Abstract

Chloroplast biogenesis describes the transition of non-photosynthetic proplastids to photosynthetically active chloroplasts in the cells of germinating seeds. Chloroplast biogenesis requires the import of thousands of nuclear-encoded preproteins by essential import receptor TOC159. We demonstrate that the SUMO (Small Ubiquitin-related Modifier) pathway crosstalks with the ubiquitin-proteasome pathway to affect TOC159 stability during early plant development. We identified a SUMO3-interacting motif (SIM) in the TOC159 GTPase domain and a SUMO3 covalent SUMOylation site in the membrane domain. A single K to R substitution (K1370R) in the M-domain disables SUMOylation. Compared to wild type TOC159, TOC159K1370R was destabilized under UPS-inducing stress conditions. However, TOC159K1370R recovered to same protein level as wild type TOC159 in the presence of a proteasome inhibitor. Thus, SUMOylation partially stabilizes TOC159 against UPS-dependent degradation under stress conditions. Our data contribute to the evolving model of tightly controlled proteostasis of the TOC159 import receptor during proplastid to chloroplast transition.

Article and author information

Author details

  1. Sonia Accossato

    Laboratoire de Physiologie Végétale, Université de Neuchâtel, Neuchâtel, Switzerland
    Competing interests
    The authors declare that no competing interests exist.
  2. Felix Kessler

    Laboratoire de Physiologie Végétale, Université de Neuchâtel, Neuchâtel, Switzerland
    For correspondence
    felix.kessler@unine.ch
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6409-5043
  3. Venkatasalam Shanmugabalaji

    Laboratoire de Physiologie Végétale, Université de Neuchâtel, Neuchâtel, Switzerland
    For correspondence
    shanmugabalaji.venkatasalam@unine.ch
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3855-6958

Funding

Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (31003A_156998)

  • Felix Kessler

Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (31003A _176191)

  • Felix Kessler

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

Reviewing Editor

  1. Heather E McFarlane, University of Toronto, Canada

Publication history

  1. Received: July 11, 2020
  2. Accepted: December 22, 2020
  3. Accepted Manuscript published: December 22, 2020 (version 1)

Copyright

© 2020, Accossato 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

  • 405
    Page views
  • 116
    Downloads
  • 0
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

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)

Download citations (links to download the citations from this article in formats compatible with various reference manager tools)

Open citations (links to open the citations from this article in various online reference manager services)

Further reading

    1. Plant Biology
    2. Structural Biology and Molecular Biophysics
    Hans-Peter Braun
    Insight

    Atomic structures of mitochondrial enzyme complexes in plants are shedding light on their multiple functions.

    1. Plant Biology
    2. Structural Biology and Molecular Biophysics
    Maria Maldonado et al.
    Research Article

    Mitochondrial complex III (CIII2) and complex IV (CIV), which can associate into a higher-order supercomplex (SC III2+IV), play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII2, CIV, and SC III2+IV from Vigna radiata determined by single-particle cryoEM. The structures reveal plant-specific differences in the MPP domain of CIII2 and define the subunit composition of CIV. Conformational heterogeneity analysis of CIII2 revealed long-range, coordinated movements across the complex, as well as the motion of CIII2’s iron-sulfur head domain. The CIV structure suggests that, in plants, proton translocation does not occur via the H channel. The supercomplex interface differs significantly from that in yeast and bacteria in its interacting subunits, angle of approach and limited interactions in the mitochondrial matrix. These structures challenge long-standing assumptions about the plant complexes and generate new mechanistic hypotheses.