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

Abstract
Data availability
Article and author information
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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

1. Alushin et al.
(2017) Actin alone
EMD-7115.

http://www.ebi.ac.uk/pdbe/
1. Alushin et al.
(2017) Rigor
EMD-7116.

http://www.ebi.ac.uk/pdbe/
1. Alushin et al.
(2017) ADP
EMD-7117.

http://www.ebi.ac.uk/pdbe/
1. Alushin et al.
(2017) Actin alone (HR MDFF)
6BNO.

https://www.rcsb.org/pdb/home/home.do
1. Alushin et al.
(2017) (averaged HR MDFF)
6BNU.

https://www.rcsb.org/pdb/home/home.do
1. Alushin et al.
(2017) Rigor (HR MDFF)
6BNP.

https://www.rcsb.org/pdb/home/home.do
1. Alushin et al.
(2017) (LPF MDFF)
6BNV.

https://www.rcsb.org/pdb/home/home.do
1. Alushin et al.
(2017) ADP (HR MDFF)
6BNQ.

https://www.rcsb.org/pdb/home/home.do
1. Alushin et al.
(2017) (LPF MDFF)
6BNW.

https://www.rcsb.org/pdb/home/home.do

Article and author information

Author details

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.
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.
Paul V Ruijgrok

Department of Bioengineering, Stanford University, Stanford, United States

Competing interests
The authors declare that no competing interests exist.
Tosan Omabegho

Department of Bioengineering, Stanford University, Stanford, United States

Competing interests
The authors declare that no competing interests exist.
Zev Bryant

Department of Bioengineering, Stanford University, Stanford, United States

Competing interests
The authors declare that no competing interests exist.
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.

"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.

Copyright

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.