Mechanistic Insights into the Active Site and Allosteric Communication Pathways in Human Nonmuscle Myosin-2C

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Abstract

Despite a generic, highly conserved motor domain, ATP turnover kinetics and their activation by F-actin vary greatly between myosin-2 isoforms. Here, we present a 2.25 Å crystal pre-powerstroke state (ADP·VO₄) structure of the human nonmuscle myosin-2C motor domain, one of the slowest myosins characterized. In combination with integrated mutagenesis, ensemble-solution kinetics, and molecular dynamics simulation approaches, the structure reveals an allosteric communication pathway that connects the distal end of the motor domain with the active site. Disruption of this pathway by mutation of hub residue R788, which forms the center of a cluster of interactions connecting the converter, the SH1-SH2 helix, the relay helix, and the lever, abolishes nonmuscle myosin-2 specific kinetic signatures. Our results provide insights into structural changes in the myosin motor domain that are triggered upon F-actin binding and contribute critically to the mechanochemical behavior of stress fibers, actin arcs, and cortical actin-based structures.

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Krishna Chinthalapudi

Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany

Competing interests
The authors declare that no competing interests exist.
Sarah M Heissler

Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany

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

Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-7784-4012
James R Sellers

Laboratory of Molecular Physiology, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, United States

For correspondence
sellersj@nhlbi.nih.gov

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0001-6296-564X
Dietmar J Manstein

Institute for Biophysical Chemistry, Hannover Medical School, Hannover, Germany

For correspondence
manstein.dietmar@mh-hannover.de

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0003-0763-0147

Funding

Deutsche Forschungsgemeinschaft (MA 1081_21-1)

Dietmar J Manstein

National Institutes of Health (Intramural Funding)

James R Sellers

Deutsche Forschungsgemeinschaft (PR 1478_2-1)

Matthias Preller

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

Copyright

This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication.