1. Cell Biology
Download icon

Actin filaments target the oligomeric maturation of the dynamin GTPase Drp1 to mitochondrial fission sites

  1. Wei-ke Ji
  2. Anna L Hatch
  3. Ronald A Merrill
  4. Stefan Strack
  5. Henry N Higgs  Is a corresponding author
  1. Geisel School of Medicine at Dartmouth, United States
  2. The University of Iowa, United States
Research Article
  • Cited 116
  • Views 5,460
  • Annotations
Cite this article as: eLife 2015;4:e11553 doi: 10.7554/eLife.11553

Abstract

While the dynamin GTPase Drp1 plays a critical role during mitochondrial fission, mechanisms controlling its recruitment to fission sites are unclear. A current assumption is that cytosolic Drp1 is recruited directly to fission sites immediately prior to fission. Using live-cell microscopy, we find evidence for a different model, progressive maturation of Drp1 oligomers on mitochondria through incorporation of smaller mitochondrially-bound Drp1 units. Maturation of a stable Drp1 oligomer does not forcibly lead to fission. Inhibiting actin polymerization, myosin IIA, or the formin INF2 reduces both un-stimulated and ionomycin-induced Drp1 accumulation and mitochondrial fission. Actin filaments bind purified Drp1 and increase GTPase activity in a manner that is synergistic with the mitochondrial protein Mff, suggesting a role for direct Drp1/actin interaction. We propose that Drp1 is in dynamic equilibrium on mitochondria in a fission-independent manner, and that fission factors such as actin filaments target productive oligomerization to fission sites.

Article and author information

Author details

  1. Wei-ke Ji

    Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Anna L Hatch

    Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Ronald A Merrill

    Department of Pharmacology, The University of Iowa, Iowa City, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Stefan Strack

    Department of Pharmacology, The University of Iowa, Iowa City, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Henry N Higgs

    Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, United States
    For correspondence
    henry.higgs@dartmouth.edu
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Pekka Lappalainen, University of Helsinki, Finland

Publication history

  1. Received: September 11, 2015
  2. Accepted: November 25, 2015
  3. Accepted Manuscript published: November 26, 2015 (version 1)
  4. Accepted Manuscript updated: November 30, 2015 (version 2)
  5. Version of Record published: February 3, 2016 (version 3)

Copyright

© 2015, Ji 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

  • 5,460
    Page views
  • 1,567
    Downloads
  • 116
    Citations

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

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. Cell Biology
    2. Neuroscience
    Friederike Elisabeth Kohrs et al.
    Tools and Resources

    Rab GTPases are molecular switches that regulate membrane trafficking in all cells. Neurons have particular demands on membrane trafficking and express numerous Rab GTPases of unknown function. Here we report the generation and characterization of molecularly defined null mutants for all 26 rab genes in Drosophila. In flies, all rab genes are expressed in the nervous system where at least half exhibit particularly high levels compared to other tissues. Surprisingly, loss of any of these 13 nervous system-enriched Rabs yielded viable and fertile flies without obvious morphological defects. However, all 13 mutants differentially affected development when challenged with different temperatures, or neuronal function when challenged with continuous stimulation. We identified a synaptic maintenance defect following continuous stimulation for six mutants, including an autophagy-independent role of rab26. The complete mutant collection generated in this study provides a basis for further comprehensive studies of Rab GTPases during development and function in vivo.

    1. Cell Biology
    Luca Minati et al.
    Tools and Resources Updated

    A vast portion of the mammalian genome is transcribed as long non-coding RNAs (lncRNAs) acting in the cytoplasm with largely unknown functions. Surprisingly, lncRNAs have been shown to interact with ribosomes, encode peptides, or act as ribosome sponges. These functions still remain mostly undetected and understudied owing to the lack of efficient tools for genome-wide simultaneous identification of ribosome-associated and peptide-producing lncRNAs. Here, we present AHA-mediated RIBOsome isolation (AHARIBO), a method for the detection of lncRNAs either untranslated, but associated with ribosomes, or encoding small peptides. Using AHARIBO in mouse embryonic stem cells during neuronal differentiation, we isolated ribosome-protected RNA fragments, translated RNAs, and corresponding de novo synthesized peptides. Besides identifying mRNAs under active translation and associated ribosomes, we found and distinguished lncRNAs acting as ribosome sponges or encoding micropeptides, laying the ground for a better functional understanding of hundreds of lncRNAs.