Expansion and concatenation of nonmuscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis

@article{Fenix2016ExpansionAC,
  title={Expansion and concatenation of nonmuscle myosin IIA filaments drive cellular contractile system formation during interphase and mitosis},
  author={Aidan M. Fenix and Nilay Taneja and Carmen A. Buttler and John R. Lewis and Schuyler B. van Engelenburg and Ryoma Ohi and Dylan T Burnette},
  journal={Molecular Biology of the Cell},
  year={2016},
  volume={27},
  pages={1465 - 1478}
}
Stacks of nonmuscle myosin IIA filaments form by the expansion of single filaments and concatenation of multiple filaments. Expansion is the dominant mechanism and is characterized by distinct structural steps. It is dependent on both motor activity and actin filament concentration. Expansion and catenation occur in both crawling and dividing cells. 

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References

SHOWING 1-10 OF 65 REFERENCES

Dissecting Temporal and Spatial Control of Cytokinesis with a Myosin II Inhibitor

TLDR
It is shown that exit from the cytokinetic phase of the cell cycle depends on ubiquitin-mediated proteolysis and continuous signals from microtubules are required to maintain the position of the cleavage furrow, and these signals control the localization of myosin II independently of other furrow components.

Three-dimensional arrangement of F-actin in the contractile ring of fission yeast

TLDR
This work considers that the contractile ring is initially assembled from a single site in the division plane and that filaments subsequently rearrange before contraction initiates, and shows that the ring filaments show mixed directionality.

Dynamic myosin phosphorylation regulates contractile pulses and tissue integrity during epithelial morphogenesis

Dynamic regulation of Myo-II by Rho kinase and myosin phosphatase organizes contractile Myo-II pulses in both space and time, which is necessary to maintain tissue integrity during morphogenesis.

Functions of Nonmuscle Myosin II in Assembly of the Cellular Contractile System

TLDR
It is proposed that activated, but unpolymerized NMII initiates focal complexes, thus providing traction for lamellipodial protrusion and activation of NMII motor activity by light chain phosphorylation is uncoupled from NMII assembly into bipolar filaments.

Unconventional Processive Mechanics of Non-muscle Myosin IIB*

TLDR
The results show that NMIIB is the first myosin II to exhibit evidence of processive stepping behavior, and support a model in whichNMIIB can readily move in both directions at stall, which may be important for a general regulator of cytoskeleton tension.

Self-organization of myosin II in reconstituted actomyosin bundles.

Kinetic Characterization of Nonmuscle Myosin IIB at the Single Molecule Level*

TLDR
The results are in good agreement with the previous steady-state and transient kinetic studies and show that the individual nonprocessive nonmuscle myosin IIB molecules form a highly processive unit when polymerized into filaments.

Mechanical integration of actin and adhesion dynamics in cell migration.

TLDR
Current knowledge of the dynamic organization of the F-actin cytoskeleton in cell migration and the regulation of focal adhesion assembly and disassembly is reviewed with an emphasis on how mechanical and biochemical signaling between these two systems regulate the coordination of physical processes in cell Migration.

Myosin II contributes to cell-scale actin network treadmilling via network disassembly

TLDR
The results establish the importance of myosin II as an enzyme for actin network disassembly and propose that gradual formation and reorganization of an actomyosin network provides an intrinsic destruction timer, enabling long-range coordination of act in network treadmilling in motile cells.

Nonmuscle myosin II exerts tension but does not translocate actin in vertebrate cytokinesis

TLDR
It is proposed that the major roles of NM II in vertebrate cell cytokinesis are to bind and cross-link actin filaments and to exert tension on actin during contractile ring constriction.
...