Abstract

The microtubule binding protein EB1 specifically targets the growing ends of microtubules in cells, where EB1 facilitates the interactions of cellular proteins with microtubule plus-ends. Microtubule end targeting of EB1 has been attributed to high affinity binding of EB1 to GTP-tubulin that is present at growing microtubule ends. However, our 3D single-molecule diffusion simulations predicted a ~6000% increase in EB1 arrivals to open, tapered microtubule tip structures relative to closed lattice conformations. Using quantitative fluorescence, single-molecule, and electron microscopy experiments, we found that the binding of EB1 onto opened, structurally disrupted microtubules was dramatically increased relative to closed, intact microtubules, regardless of hydrolysis state. Correspondingly, in cells, the blunting of growing microtubule plus-ends by Vinblastine was correlated with reduced EB1 targeting. Together, our results suggest that microtubule structural recognition, based on a fundamental diffusion-limited binding model, facilitates the tip tracking of EB1 at growing microtubule ends.

Data availability

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

Article and author information

Author details

  1. Taylor A Reid

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Courtney Coombes

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Soumya Mukherjee

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Rebecca R Goldblum

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Kyle White

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Sneha Parmar

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Mark McClellan

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Marija Zanic

    Department of Cell and Developmental Biology, Vanderbilt University, Nashville, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5127-5819
  9. Naomi Courtemanche

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Melissa K Gardner

    Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, United States
    For correspondence
    klei0091@umn.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5906-7363

Funding

National Institutes of Health (R01-GM103833)

  • Melissa K Gardner

National Institutes of Health (R35-GM126974)

  • Melissa K Gardner

National Science Foundation (1350741)

  • Melissa K Gardner

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

Copyright

© 2019, Reid 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

  • 3,672
    views
  • 469
    downloads
  • 28
    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. Taylor A Reid
  2. Courtney Coombes
  3. Soumya Mukherjee
  4. Rebecca R Goldblum
  5. Kyle White
  6. Sneha Parmar
  7. Mark McClellan
  8. Marija Zanic
  9. Naomi Courtemanche
  10. Melissa K Gardner
(2019)
Structural state recognition facilitates tip tracking of EB1 at growing microtubule ends
eLife 8:e48117.
https://doi.org/10.7554/eLife.48117

Share this article

https://doi.org/10.7554/eLife.48117

Further reading

    1. Cell Biology
    Affiong Ika Oqua, Kin Chao ... Alejandra Tomas
    Research Article

    G protein-coupled receptors (GPCRs) are integral membrane proteins which closely interact with their plasma membrane lipid microenvironment. Cholesterol is a lipid enriched at the plasma membrane with pivotal roles in the control of membrane fluidity and maintenance of membrane microarchitecture, directly impacting on GPCR stability, dynamics, and function. Cholesterol extraction from pancreatic beta cells has previously been shown to disrupt the internalisation, clustering, and cAMP responses of the glucagon-like peptide-1 receptor (GLP-1R), a class B1 GPCR with key roles in the control of blood glucose levels via the potentiation of insulin secretion in beta cells and weight reduction via the modulation of brain appetite control centres. Here, we unveil the detrimental effect of a high cholesterol diet on GLP-1R-dependent glucoregulation in vivo, and the improvement in GLP-1R function that a reduction in cholesterol synthesis using simvastatin exerts in pancreatic islets. We next identify and map sites of cholesterol high occupancy and residence time on active vs inactive GLP-1Rs using coarse-grained molecular dynamics (cgMD) simulations, followed by a screen of key residues selected from these sites and detailed analyses of the effects of mutating one of these, Val229, to alanine on GLP-1R-cholesterol interactions, plasma membrane behaviours, clustering, trafficking and signalling in INS-1 832/3 rat pancreatic beta cells and primary mouse islets, unveiling an improved insulin secretion profile for the V229A mutant receptor. This study (1) highlights the role of cholesterol in regulating GLP-1R responses in vivo; (2) provides a detailed map of GLP-1R - cholesterol binding sites in model membranes; (3) validates their functional relevance in beta cells; and (4) highlights their potential as locations for the rational design of novel allosteric modulators with the capacity to fine-tune GLP-1R responses.

    1. Cell Biology
    2. Immunology and Inflammation
    Alejandro Rosell, Agata Adelajda Krygowska ... Esther Castellano Sanchez
    Research Article

    Macrophages are crucial in the body’s inflammatory response, with tightly regulated functions for optimal immune system performance. Our study reveals that the RAS–p110α signalling pathway, known for its involvement in various biological processes and tumourigenesis, regulates two vital aspects of the inflammatory response in macrophages: the initial monocyte movement and later-stage lysosomal function. Disrupting this pathway, either in a mouse model or through drug intervention, hampers the inflammatory response, leading to delayed resolution and the development of more severe acute inflammatory reactions in live models. This discovery uncovers a previously unknown role of the p110α isoform in immune regulation within macrophages, offering insight into the complex mechanisms governing their function during inflammation and opening new avenues for modulating inflammatory responses.