Cryo-EM structures reveal specialization at the myosin VI-actin interface and a mechanism of force sensitivity

  1. Pinar S Gurel
  2. Laura Y Kim
  3. Paul V Ruijgrok
  4. Tosan Omabegho
  5. Zev Bryant
  6. Gregory M Alushin  Is a corresponding author
  1. National Heart, Blood, and Lung Institute, United States
  2. Stanford University, United States

Abstract

Despite extensive scrutiny of the myosin superfamily, the lack of high-resolution structures of actin-bound states has prevented a complete description of its mechanochemical cycle and limited insight into how sequence and structural diversification of the motor domain gives rise to specialized functional properties. Here we present cryo-EM structures of the unique minus-end directed myosin VI motor domain in rigor (4.6 Å) and Mg-ADP (5.5 Å) states bound to F-actin. Comparison to the myosin IIC-F-actin rigor complex reveals an almost complete lack of conservation of residues at the actin-myosin interface despite preservation of the primary sequence regions composing it, suggesting an evolutionary path for motor specialization. Additionally, analysis of the transition from ADP to rigor provides a structural rationale for force sensitivity in this step of the mechanochemical cycle. Finally, we observe reciprocal rearrangements in actin and myosin accompanying the transition between these states, supporting a role for actin structural plasticity during force generation by myosin VI.

Data availability

The following data sets were generated

Article and author information

Author details

  1. Pinar S Gurel

    Cell Biology and Physiology Center, National Heart, Blood, and Lung Institute, Bethesda, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Laura Y Kim

    Cell Biology and Physiology Center, National Heart, Blood, and Lung Institute, Bethesda, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Paul V Ruijgrok

    Department of Bioengineering, Stanford University, Stanford, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Tosan Omabegho

    Department of Bioengineering, Stanford University, Stanford, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Zev Bryant

    Department of Bioengineering, Stanford University, Stanford, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Gregory M Alushin

    Cell Biology and Physiology Center, National Heart, Blood, and Lung Institute, Bethesda, United States
    For correspondence
    galushin@rockefeller.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-7250-4484

Funding

W. M. Keck Foundation

  • Zev Bryant

Human Frontier Science Program (Long-Term Fellowship)

  • Paul V Ruijgrok

National Heart, Lung, and Blood Institute

  • Gregory M Alushin

Rockefeller University (Women & Science Fellowship)

  • Pinar S Gurel

National Institutes of Health (F32GM094420)

  • Tosan Omabegho

National Institutes of Health (1DP2 OD004690)

  • Zev Bryant

National Institutes of Health (5DP5OD017885)

  • Gregory M Alushin

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

Reviewing Editor

  1. Edward H Egelman, University of Virginia, United States

Version history

  1. Received: August 9, 2017
  2. Accepted: December 2, 2017
  3. Accepted Manuscript published: December 4, 2017 (version 1)
  4. Version of Record published: January 10, 2018 (version 2)

Copyright

© 2017, Gurel 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

  • 4,179
    views
  • 697
    downloads
  • 46
    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. Pinar S Gurel
  2. Laura Y Kim
  3. Paul V Ruijgrok
  4. Tosan Omabegho
  5. Zev Bryant
  6. Gregory M Alushin
(2017)
Cryo-EM structures reveal specialization at the myosin VI-actin interface and a mechanism of force sensitivity
eLife 6:e31125.
https://doi.org/10.7554/eLife.31125

Share this article

https://doi.org/10.7554/eLife.31125

Further reading

    1. Cell Biology
    2. Structural Biology and Molecular Biophysics
    Shun Kai Yang, Shintaroh Kubo ... Khanh Huy Bui
    Research Article

    Acetylation of α-tubulin at the lysine 40 residue (αK40) by αTAT1/MEC-17 acetyltransferase modulates microtubule properties and occurs in most eukaryotic cells. Previous literatures suggest that acetylated microtubules are more stable and damage resistant. αK40 acetylation is the only known microtubule luminal post-translational modification site. The luminal location suggests that the modification tunes the lateral interaction of protofilaments inside the microtubule. In this study, we examined the effect of tubulin acetylation on the doublet microtubule (DMT) in the cilia of Tetrahymena thermophila using a combination of cryo-electron microscopy, molecular dynamics, and mass spectrometry. We found that αK40 acetylation exerts a small-scale effect on the DMT structure and stability by influencing the lateral rotational angle. In addition, comparative mass spectrometry revealed a link between αK40 acetylation and phosphorylation in cilia.

    1. Structural Biology and Molecular Biophysics
    Sebastian Jojoa-Cruz, Adrienne E Dubin ... Andrew B Ward
    Research Advance

    The dimeric two-pore OSCA/TMEM63 family has recently been identified as mechanically activated ion channels. Previously, based on the unique features of the structure of OSCA1.2, we postulated the potential involvement of several structural elements in sensing membrane tension (Jojoa-Cruz et al., 2018). Interestingly, while OSCA1, 2, and 3 clades are activated by membrane stretch in cell-attached patches (i.e. they are stretch-activated channels), they differ in their ability to transduce membrane deformation induced by a blunt probe (poking). Here, in an effort to understand the domains contributing to mechanical signal transduction, we used cryo-electron microscopy to solve the structure of Arabidopsis thaliana (At) OSCA3.1, which, unlike AtOSCA1.2, only produced stretch- but not poke-activated currents in our initial characterization (Murthy et al., 2018). Mutagenesis and electrophysiological assessment of conserved and divergent putative mechanosensitive features of OSCA1.2 reveal a selective disruption of the macroscopic currents elicited by poking without considerable effects on stretch-activated currents (SAC). Our results support the involvement of the amphipathic helix and lipid-interacting residues in the membrane fenestration in the response to poking. Our findings position these two structural elements as potential sources of functional diversity within the family.