Format

Send to

Choose Destination
Philos Trans R Soc Lond B Biol Sci. 2018 May 26;373(1747). pii: 20170114. doi: 10.1098/rstb.2017.0114.

Ordering of myosin II filaments driven by mechanical forces: experiments and theory.

Author information

1
James Franck Institute, University of Chicago, Chicago, IL 60637, USA.
2
Mechanobiology Institute, National University of Singapore, Singapore 117411, Republic of Singapore.
3
Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
4
Aix Marseille University, CNRS, IBDM, 13288 Marseille, France frank.schnorrer@univ-amu.fr.
5
Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 76100, Israel sam.safran@weizmann.ac.il.
6
Mechanobiology Institute, National University of Singapore, Singapore 117411, Republic of Singapore alexander.bershadsky@weizmann.ac.il.
7
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel.

Abstract

Myosin II filaments form ordered superstructures in both cross-striated muscle and non-muscle cells. In cross-striated muscle, myosin II (thick) filaments, actin (thin) filaments and elastic titin filaments comprise the stereotypical contractile units of muscles called sarcomeres. Linear chains of sarcomeres, called myofibrils, are aligned laterally in registry to form cross-striated muscle cells. The experimentally observed dependence of the registered organization of myofibrils on extracellular matrix elasticity has been proposed to arise from the interactions of sarcomeric contractile elements (considered as force dipoles) through the matrix. Non-muscle cells form small bipolar filaments built of less than 30 myosin II molecules. These filaments are associated in registry forming superstructures ('stacks') orthogonal to actin filament bundles. Formation of myosin II filament stacks requires the myosin II ATPase activity and function of the actin filament crosslinking, polymerizing and depolymerizing proteins. We propose that the myosin II filaments embedded into elastic, intervening actin network (IVN) function as force dipoles that interact attractively through the IVN. This is in analogy with the theoretical picture developed for myofibrils where the elastic medium is now the actin cytoskeleton itself. Myosin stack formation in non-muscle cells provides a novel mechanism for the self-organization of the actin cytoskeleton at the level of the entire cell.This article is part of the theme issue 'Self-organization in cell biology'.

KEYWORDS:

force dipoles; non-muscle myosin filaments; sarcomere; stress fibres; striated muscle; super-resolution microscopy

PMID:
29632266
PMCID:
PMC5904300
[Available on 2019-05-26]
DOI:
10.1098/rstb.2017.0114

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center