Microtubule rescue at midzone edges promotes overlap stability and prevents spindle collapse during anaphase B

  1. Manuel Lera-Ramirez  Is a corresponding author
  2. François J Nédélec  Is a corresponding author
  3. Phong T Tran  Is a corresponding author
  1. Institut Curie, France
  2. Cambridge University, United Kingdom

Abstract

During anaphase B, molecular motors slide interpolar microtubules to elongate the mitotic spindle, contributing to the separation of chromosomes. However, sliding of antiparallel microtubules reduces their overlap, which may lead to spindle breakage, unless microtubules grow to compensate sliding. How sliding and growth are coordinated is still poorly understood. In this study, we have used the fission yeast S. pombe to measure microtubule dynamics during anaphase B. We report that the coordination of microtubule growth and sliding relies on promoting rescues at the midzone edges. This makes microtubules stable from pole to midzone, while their distal parts including the plus ends alternate between assembly and disassembly. Consequently, the midzone keeps a constant length throughout anaphase, enabling sustained sliding without the need for a precise regulation of microtubule growth speed. Additionally, we found that in S. pombe, which undergoes closed mitosis, microtubule growth speed decreases when the nuclear membrane wraps around the spindle midzone.

Data availability

Source code to reproduce and analyse the simulations is deposited in github at https://github.com/manulera/simulationsLeraRamirez2021Source code to annotate and analyse kymographs is deposited in github athttps://github.com/manulera/KymoAnalyzerSource code to find spindles in microscopy images is deposited in github at https://github.com/manulera/ImageAnalysisFunctions/tree/master/detection_functions/spindleWe have uploaded the source data for all figures as comma separated values files.

The following data sets were generated

Article and author information

Author details

  1. Manuel Lera-Ramirez

    CNRS, UMR 144, Institut Curie, Paris, France
    For correspondence
    manuel.lera-ramirez@curie.fr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8666-9746
  2. François J Nédélec

    Sainsbury Laboratory, Cambridge University, Cambridge, United Kingdom
    For correspondence
    francois.nedelec@slcu.cam.ac.uk
    Competing interests
    The authors declare that no competing interests exist.
  3. Phong T Tran

    CNRS, UMR 144, Institut Curie, Paris, France
    For correspondence
    phong.tran@curie.fr
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2410-2277

Funding

H2020 Marie Skłodowska-Curie Actions (675737)

  • Manuel Lera-Ramirez

Gatsby Charitable Foundation

  • François J Nédélec

Institut National Du Cancer

  • Phong T Tran

Fondation ARC pour la Recherche sur le Cancer

  • Phong T Tran

Ligue Contre le Cancer

  • Phong T Tran

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

Reviewing Editor

  1. Silke Hauf, Virginia Tech, United States

Version history

  1. Received: July 29, 2021
  2. Preprint posted: August 6, 2021 (view preprint)
  3. Accepted: March 15, 2022
  4. Accepted Manuscript published: March 16, 2022 (version 1)
  5. Version of Record published: April 19, 2022 (version 2)

Copyright

© 2022, Lera-Ramirez 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

  • 733
    Page views
  • 162
    Downloads
  • 1
    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)

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. Manuel Lera-Ramirez
  2. François J Nédélec
  3. Phong T Tran
(2022)
Microtubule rescue at midzone edges promotes overlap stability and prevents spindle collapse during anaphase B
eLife 11:e72630.
https://doi.org/10.7554/eLife.72630

Further reading

    1. Cell Biology
    2. Computational and Systems Biology
    Breanne Sparta, Nont Kosaisawe ... John G Albeck
    Research Article Updated

    mTORC1 senses nutrients and growth factors and phosphorylates downstream targets, including the transcription factor TFEB, to coordinate metabolic supply and demand. These functions position mTORC1 as a central controller of cellular homeostasis, but the behavior of this system in individual cells has not been well characterized. Here, we provide measurements necessary to refine quantitative models for mTORC1 as a metabolic controller. We developed a series of fluorescent protein-TFEB fusions and a multiplexed immunofluorescence approach to investigate how combinations of stimuli jointly regulate mTORC1 signaling at the single-cell level. Live imaging of individual MCF10A cells confirmed that mTORC1-TFEB signaling responds continuously to individual, sequential, or simultaneous treatment with amino acids and the growth factor insulin. Under physiologically relevant concentrations of amino acids, we observe correlated fluctuations in TFEB, AMPK, and AKT signaling that indicate continuous activity adjustments to nutrient availability. Using partial least squares regression modeling, we show that these continuous gradations are connected to protein synthesis rate via a distributed network of mTORC1 effectors, providing quantitative support for the qualitative model of mTORC1 as a homeostatic controller and clarifying its functional behavior within individual cells.

    1. Cell Biology
    2. Genetics and Genomics
    Christopher H Emfinger, Lauren E Clark ... Alan D Attie
    Research Article

    Insufficient insulin secretion to meet metabolic demand results in diabetes. The intracellular flux of Ca2+ into β-cells triggers insulin release. Since genetics strongly influences variation in islet secretory responses, we surveyed islet Ca2+ dynamics in eight genetically diverse mouse strains. We found high strain variation in response to four conditions: (1) 8 mM glucose; (2) 8 mM glucose plus amino acids; (3) 8 mM glucose, amino acids, plus 10 nM glucose-dependent insulinotropic polypeptide (GIP); and (4) 2 mM glucose. These stimuli interrogate β-cell function, α- to β-cell signaling, and incretin responses. We then correlated components of the Ca2+ waveforms to islet protein abundances in the same strains used for the Ca2+ measurements. To focus on proteins relevant to human islet function, we identified human orthologues of correlated mouse proteins that are proximal to glycemic-associated single-nucleotide polymorphisms in human genome-wide association studies. Several orthologues have previously been shown to regulate insulin secretion (e.g. ABCC8, PCSK1, and GCK), supporting our mouse-to-human integration as a discovery platform. By integrating these data, we nominate novel regulators of islet Ca2+ oscillations and insulin secretion with potential relevance for human islet function. We also provide a resource for identifying appropriate mouse strains in which to study these regulators.