The Piezo channel is used by migrating cells to sense compressive load

Mapping Intimacies ◽

10.1101/534172 ◽

2019 ◽

Cited By ~ 1

Author(s):

Nishit Srivastava ◽

David Traynor ◽

Alexandre J. Kabla ◽

Robert R. Kay

Keyword(s):

Myosin Ii ◽

Compressive Load ◽

Cytosolic Calcium ◽

Uniaxial Pressure ◽

Actin Dynamics ◽

Physical Barriers ◽

Sense And Respond ◽

Null Mutants ◽

Soft Agarose ◽

Migrating Cells

AbstractMigrating cells face varied mechanical and physical barriers in physiological environments, but how they sense and respond to them remains to be fully understood. We used a custom-built ‘cell squasher’ to apply uniaxial pressure to Dictyostelium cells migrating under soft agarose. Within 10 seconds of application, loads of as little as 100 Pa cause cells to move using blebs instead of pseudopods. Cells lose volume and surface area under pressure and their actin dynamics are perturbed. Myosin-II is recruited to the cortex, potentially increasing contractility and so driving blebbing. The blebbing response depends on extra-cellular calcium, is accompanied by increased cytosolic calcium and largely abrogated in null mutants of the Piezo stretch-operated channel. We propose that migrating cells sense mechanical force through mechano-sensitive channels, leading to an influx of calcium and cortical recruitment of myosin, thus re-directing the motile apparatus to produce blebs rather than pseudopods.

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Pressure sensing through Piezo channels controls whether cells migrate with blebs or pseudopods

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1905730117 ◽

2020 ◽

Vol 117 (5) ◽

pp. 2506-2512 ◽

Cited By ~ 11

Author(s):

Nishit Srivastava ◽

David Traynor ◽

Matthieu Piel ◽

Alexandre J. Kabla ◽

Robert R. Kay

Keyword(s):

Calcium Influx ◽

Myosin Ii ◽

Cytosolic Calcium ◽

Uniaxial Pressure ◽

Mechanical Resistance ◽

Mechanical Forces ◽

Pressure Sensing ◽

Power Cell ◽

A Cell ◽

Migrating Cells

Blebs and pseudopods can both power cell migration, with blebs often favored in tissues, where cells encounter increased mechanical resistance. To investigate how migrating cells detect and respond to mechanical forces, we used a “cell squasher” to apply uniaxial pressure to Dictyostelium cells chemotaxing under soft agarose. As little as 100 Pa causes a rapid (<10 s), sustained shift to movement with blebs rather than pseudopods. Cells are flattened under load and lose volume; the actin cytoskeleton is reorganized, with myosin II recruited to the cortex, which may pressurize the cytoplasm for blebbing. The transition to bleb-driven motility requires extracellular calcium and is accompanied by increased cytosolic calcium. It is largely abrogated in cells lacking the Piezo stretch-operated channel; under load, these cells persist in using pseudopods and chemotax poorly. We propose that migrating cells sense pressure through Piezo, which mediates calcium influx, directing movement with blebs instead of pseudopods.

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Formation of neutrophil extracellular traps requires actin cytoskeleton rearrangements

Blood ◽

10.1182/blood.2021013565 ◽

2022 ◽

Author(s):

Evelien G.G. Sprenkeler ◽

Anton T.J. Tool ◽

Stefanie Henriet ◽

Robin van Bruggen ◽

Taco W. Kuijpers

Keyword(s):

Actin Polymerization ◽

Nuclear Dna ◽

Myosin Ii ◽

Neutrophil Extracellular Traps ◽

Actin Dynamics ◽

Polymerization Process ◽

Effector Cells ◽

Extracellular Traps ◽

Cytoskeleton Rearrangements ◽

Cellular Components

Neutrophils are important effector cells in the host defense against invading micro-organisms. One of the mechanisms they employ to eliminate pathogens is the release of neutrophil extracellular traps (NETs). Although NET release and subsequent cell death known as NETosis have been intensively studied, the cellular components and factors determining or facilitating the formation of NETs remain incompletely understood. Using various actin polymerization and myosin II modulators on neutrophils from healthy individuals, we show that intact F-actin dynamics and myosin II function are essential for NET formation when induced by different stimuli, i.e. phorbol 12-myristate 13-acetate, monosodium urate crystals and Candida albicans. The role of actin polymerization in NET formation could not be explained by the lack of reactive oxygen species production or granule release, which were normal or enhanced under the given conditions. Neutrophils from patients with very rare inherited actin polymerization defects by either ARPC1B- or MKL1-deficiency also failed to show NETosis. We found that upon inhibition of actin dynamics there is a lack of translocation of NE to the nucleus, which may well explain the impaired NET formation. Collectively, our data illustrate the essential requirement of an intact and active actin polymerization process, as well as active myosin II to enable the release of nuclear DNA by neutrophils during NET formation.

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Myosin 1b is an actin depolymerase

Nature Communications ◽

10.1038/s41467-019-13160-y ◽

2019 ◽

Vol 10 (1) ◽

Cited By ~ 5

Author(s):

Julien Pernier ◽

Remy Kusters ◽

Hugo Bousquet ◽

Thibaut Lagny ◽

Antoine Morchain ◽

...

Keyword(s):

Myosin Ii ◽

Actin Dynamics ◽

Myosin Motor ◽

Actin Depolymerization ◽

Cellular Processes ◽

Myosin Motors ◽

Singular Interactions ◽

Sliding Motility

AbstractThe regulation of actin dynamics is essential for various cellular processes. Former evidence suggests a correlation between the function of non-conventional myosin motors and actin dynamics. Here we investigate the contribution of myosin 1b to actin dynamics using sliding motility assays. We observe that sliding on myosin 1b immobilized or bound to a fluid bilayer enhances actin depolymerization at the barbed end, while sliding on myosin II, although 5 times faster, has no effect. This work reveals a non-conventional myosin motor as another type of depolymerase and points to its singular interactions with the actin barbed end.

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Genetic suppression of defective profilin by attenuated Myosin II reveals a potential role for Myosin II in actin dynamics in vivo in fission yeast

Molecular Biology of the Cell ◽

10.1091/mbc.e20-04-0224 ◽

2020 ◽

Vol 31 (19) ◽

pp. 2107-2114 ◽

Cited By ~ 1

Author(s):

Paola Zambon ◽

Saravanan Palani ◽

Shekhar Sanjay Jadhav ◽

Pananghat Gayathri ◽

Mohan K. Balasubramanian

Keyword(s):

Fission Yeast ◽

Double Mutant ◽

Potential Role ◽

Myosin Ii ◽

Model Organism ◽

Actin Dynamics ◽

Mutant Analysis ◽

Genetic Suppression

This work reveals an in vivo role for Myosin II in actin dynamics, potentially in its disassembly and turnover. The work uses double mutant analysis to arrive at this conclusion using the fission yeast as a model organism.

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Thrombin-induced GPIb-IX centralization on the platelet surface requires actin assembly and myosin II activation

Blood ◽

10.1182/blood.v87.2.618.bloodjournal872618 ◽

1996 ◽

Vol 87 (2) ◽

pp. 618-629 ◽

Cited By ~ 48

Author(s):

TJ Kovacsovics ◽

JH Hartwig

Keyword(s):

Actin Filaments ◽

Myosin Ii ◽

Surface Expression ◽

Membrane Skeleton ◽

Cytosolic Calcium ◽

Human Platelets ◽

Actin Binding ◽

Actin Assembly ◽

Platelet Surface ◽

Von Willebrand

In resting platelets, the GPIb-IX complex, the receptor for the von Willebrand factor (vWF), is linked to underlying actin filaments by actin-binding protein (ABP-280). Thrombin stimulation of human platelets leads to a decrease in the surface expression of the GPIb-IX complex, which is redistributed from the platelet surface into the open canalicular system (OCS). Because the centralization of GPIb-IX is inhibited by cytochalasin, it is believed to be linked to actin cytoskeletal rearrangements that take place during platelet activation. We have further characterized the mechanism of GPIb-IX centralization in platelets in suspension. Following thrombin stimulation, GPIb-IX shifts from the membrane skeleton of the resting cell to the cytoskeleton of the activated cell in a reaction sensitive to cytochalasin B. The cytoskeletal association of GPIb-IX involves ABP- 280, as it correlates with the incorporation of ABP-280 into the activated cytoskeleton and because no dissociation of the ABP-280/GPIb- IX complexes is detected after thrombin activation. However, the incorporation of GPIb-IX into the cytoskeleton is complete within 1 minute, whereas GPIb-IX centralization requires 5 to 10 minutes for completion. The movement of GPIb-IX to the cytoskeleton of activated platelets is therefore necessary, but not sufficient for GPIb-IX centralization. Blockage of cytosolic calcium increases induced by thrombin by loading with the cell permeant calcium chelator Quin-2 AM inhibited GPIb-IX centralization by 70%, but did not prevent its association with the activated cytoskeleton. Quin-2 loading did, however, decrease the incorporation of myosin II into the activated cytoskeleton. The role of myosin II was further probed using the myosin light chain kinase (MLCK) inhibitor wortmannin. Wortmannin prevents myosin II association to the activated cytoskeleton and inhibits GPIb- IX centralization by 50%, without affecting actin assembly or the association of GPIb-IX to the cytoskeleton. Only micromolar concentrations of wortmannin, high enough to inhibit MLCK, prevent GPIb- IX centralization. These results indicate that thrombin-induced GPIb-IX centralization requires a minimum of two steps, one associating GPIb-IX to the activated cytoskeleton and the second requiring myosin II activation. The involvement of myosin II implies that GPIb-IX/ABP-280 complexes, linked to actin filaments, are pulled into the cell center, and that platelets may exert contractile tension on vWF bound to its receptor.

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Scribble, Lgl1, and myosin II form a complex in vivo to promote directed cell migration

Molecular Biology of the Cell ◽

10.1091/mbc.e19-11-0657 ◽

2020 ◽

Vol 31 (20) ◽

pp. 2234-2248

Author(s):

Maha Abedrabbo ◽

Shoshana Ravid

Keyword(s):

Cell Migration ◽

Cell Adhesion ◽

Myosin Ii ◽

Leading Edge ◽

Directed Cell Migration ◽

Lethal Giant Larvae ◽

And Migration ◽

Migrating Cells

Here we show that Scribble (Scrib), Lethal giant larvae 1 (Lgl1), and myosin II form a complex in vivo and colocalize at the cell leading edge of migrating cells, and this colocalization is interdependent. Scrib and Lgl1 are required for proper cell adhesion, polarity, and migration.

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Linking Ras to myosin function: RasGEF Q, a Dictyostelium exchange factor for RasB, affects myosin II functions

The Journal of Cell Biology ◽

10.1083/jcb.200710111 ◽

2008 ◽

Vol 181 (5) ◽

pp. 747-760 ◽

Cited By ~ 16

Author(s):

Subhanjan Mondal ◽

Deenadayalan Bakthavatsalam ◽

Paul Steimle ◽

Berthold Gassen ◽

Francisco Rivero ◽

...

Keyword(s):

Cell Polarity ◽

Cell Sorting ◽

Myosin Ii ◽

Guanine Nucleotide ◽

Nucleotide Exchange ◽

Exchange Factor ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factor ◽

Myosin Heavy Chain Kinase ◽

Null Mutants

Ras guanine nucleotide exchange factor (GEF) Q, a nucleotide exchange factor from Dictyostelium discoideum, is a 143-kD protein containing RasGEF domains and a DEP domain. We show that RasGEF Q can bind to F-actin, has the potential to form complexes with myosin heavy chain kinase (MHCK) A that contain active RasB, and is the predominant exchange factor for RasB. Overexpression of the RasGEF Q GEF domain activates RasB, causes enhanced recruitment of MHCK A to the cortex, and leads to cytokinesis defects in suspension, phenocopying cells expressing constitutively active RasB, and myosin-null mutants. RasGEF Q− mutants have defects in cell sorting and slug migration during later stages of development, in addition to cell polarity defects. Furthermore, RasGEF Q− mutants have increased levels of unphosphorylated myosin II, resulting in myosin II overassembly. Collectively, our results suggest that starvation signals through RasGEF Q to activate RasB, which then regulates processes requiring myosin II.

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