A Stochastic Modelling Framework for Single Cell Migration: Coupling Contractility and Focal Adhesions

The interaction of the actin cytoskeleton with cell–substrate adhesions is necessary for cell migration. While the trajectories of motile cells have a stochastic character, investigations of cell motility mechanisms rarely elaborate on the origins of the observed randomness. Here, guided by a few fundamental attributes of cell motility, I construct a minimal stochastic cell migration model from ground-up. The resulting model couples a deterministic actomyosin contractility mechanism with stochastic cell–substrate adhesion kinetics, and yields a well-defined piecewise deterministic process. Numerical simulations reproduce several experimentally observed results, including anomalous diffusion, tactic migration and contact guidance. This work provides a basis for the development of cell–cell collision and population migration models.

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Supervillin modulation of focal adhesions involving TRIP6/ZRP-1

The Journal of Cell Biology ◽

10.1083/jcb.200512051 ◽

2006 ◽

Vol 174 (3) ◽

pp. 447-458 ◽

Cited By ~ 36

Author(s):

Norio Takizawa ◽

Tara C. Smith ◽

Thomas Nebl ◽

Jessica L. Crowley ◽

Stephen J. Palmieri ◽

...

Keyword(s):

Focal Adhesions ◽

Stress Fibers ◽

Regulatory Sequence ◽

Interacting Protein ◽

Substrate Adhesion ◽

Lim Domains ◽

Cell Substrate ◽

Thyroid Receptor ◽

And Function ◽

Cell Substrate Adhesion

Cell–substrate contacts, called focal adhesions (FAs), are dynamic in rapidly moving cells. We show that supervillin (SV)—a peripheral membrane protein that binds myosin II and F-actin in such cells—negatively regulates stress fibers, FAs, and cell–substrate adhesion. The major FA regulatory sequence within SV (SV342-571) binds to the LIM domains of two proteins in the zyxin family, thyroid receptor–interacting protein 6 (TRIP6) and lipoma-preferred partner (LPP), but not to zyxin itself. SV and TRIP6 colocalize within large FAs, where TRIP6 may help recruit SV. RNAi-mediated decreases in either protein increase cell adhesion to fibronectin. TRIP6 partially rescues SV effects on stress fibers and FAs, apparently by mislocating SV away from FAs. Thus, SV interactions with TRIP6 at FAs promote loss of FA structure and function. SV and TRIP6 binding partners suggest several specific mechanisms through which the SV–TRIP6 interaction may regulate FA maturation and/or disassembly.

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The interplay of cell–cell and cell–substrate adhesion in collective cell migration

Journal of The Royal Society Interface ◽

10.1098/rsif.2014.0684 ◽

2014 ◽

Vol 11 (100) ◽

pp. 20140684 ◽

Cited By ~ 16

Author(s):

Chenlu Wang ◽

Sagar Chowdhury ◽

Meghan Driscoll ◽

Carole A. Parent ◽

S. K. Gupta ◽

...

Keyword(s):

Cell Migration ◽

Cell Surface ◽

Actin Polymerization ◽

Collective Cell Migration ◽

Cell Contacts ◽

Substrate Adhesion ◽

Cell Substrate ◽

Cell Shapes ◽

Cell Substrate Adhesion ◽

Cell Cell

Collective cell migration often involves notable cell–cell and cell–substrate adhesions and highly coordinated motion of touching cells. We focus on the interplay between cell–substrate adhesion and cell–cell adhesion. We show that the loss of cell-surface contact does not significantly alter the dynamic pattern of protrusions and retractions of fast migrating amoeboid cells ( Dictyostelium discoideum ), but significantly changes their ability to adhere to other cells. Analysis of the dynamics of cell shapes reveals that cells that are adherent to a surface may coordinate their motion with neighbouring cells through protrusion waves that travel across cell–cell contacts. However, while shape waves exist if cells are detached from surfaces, they do not couple cell to cell. In addition, our investigation of actin polymerization indicates that loss of cell-surface adhesion changes actin polymerization at cell–cell contacts. To further investigate cell–cell/cell–substrate interactions, we used optical micromanipulation to form cell–substrate contact at controlled locations. We find that both cell-shape dynamics and cytoskeletal activity respond rapidly to the formation of cell–substrate contact.

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Extracellular Signalling Modulates Scar/WAVE Complex Activity through Abi Phosphorylation

Cells ◽

10.3390/cells10123485 ◽

2021 ◽

Vol 10 (12) ◽

pp. 3485

Author(s):

Shashi Prakash Singh ◽

Peter A. Thomason ◽

Robert H. Insall

Keyword(s):

Cell Migration ◽

Environmental Cues ◽

Complex Activity ◽

Extracellular Signals ◽

Substrate Adhesion ◽

Cell Substrate ◽

Environmental Responses ◽

Cell Substrate Adhesion ◽

Extracellular Signalling ◽

Wave Complex

The lamellipodia and pseudopodia of migrating cells are produced and maintained by the Scar/WAVE complex. Thus, actin-based cell migration is largely controlled through regulation of Scar/WAVE. Here, we report that the Abi subunit—but not Scar—is phosphorylated in response to extracellular signalling in Dictyostelium cells. Like Scar, Abi is phosphorylated after the complex has been activated, implying that Abi phosphorylation modulates pseudopodia, rather than causing new ones to be made. Consistent with this, Scar complex mutants that cannot bind Rac are also not phosphorylated. Several environmental cues also affect Abi phosphorylation—cell-substrate adhesion promotes it and increased extracellular osmolarity diminishes it. Both unphosphorylatable and phosphomimetic Abi efficiently rescue the chemotaxis of Abi KO cells and pseudopodia formation, confirming that Abi phosphorylation is not required for activation or inactivation of the Scar/WAVE complex. However, pseudopodia and Scar patches in the cells with unphosphorylatable Abi protrude for longer, altering pseudopod dynamics and cell speed. Dictyostelium, in which Scar and Abi are both unphosphorylatable, can still form pseudopods, but migrate substantially faster. We conclude that extracellular signals and environmental responses modulate cell migration by tuning the behaviour of the Scar/WAVE complex after it has been activated.

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α-Tubulin K40 acetylation is required for contact inhibition of proliferation and cell–substrate adhesion

Molecular Biology of the Cell ◽

10.1091/mbc.e13-10-0609 ◽

2014 ◽

Vol 25 (12) ◽

pp. 1854-1866 ◽

Cited By ~ 48

Author(s):

Andrea Aguilar ◽

Lars Becker ◽

Thomas Tedeschi ◽

Stefan Heller ◽

Carlo Iomini ◽

...

Keyword(s):

Cell Density ◽

Hippo Pathway ◽

Focal Adhesions ◽

Contact Inhibition ◽

Inhibition Of Proliferation ◽

Genetic Ablation ◽

Substrate Adhesion ◽

Cell Substrate ◽

The Hippo Pathway ◽

Cell Substrate Adhesion

Acetylation of α-tubulin on lysine 40 marks long-lived microtubules in structures such as axons and cilia, and yet the physiological role of α-tubulin K40 acetylation is elusive. Although genetic ablation of the α-tubulin K40 acetyltransferase αTat1 in mice did not lead to detectable phenotypes in the developing animals, contact inhibition of proliferation and cell–substrate adhesion were significantly compromised in cultured αTat1−/− fibroblasts. First, αTat1−/− fibroblasts kept proliferating beyond the confluent monolayer stage. Congruently, αTat1−/− cells failed to activate Hippo signaling in response to increased cell density, and the microtubule association of the Hippo regulator Merlin was disrupted. Second, αTat1−/− cells contained very few focal adhesions, and their ability to adhere to growth surfaces was greatly impaired. Whereas the catalytic activity of αTAT1 was dispensable for monolayer formation, it was necessary for cell adhesion and restrained cell proliferation and activation of the Hippo pathway at elevated cell density. Because α-tubulin K40 acetylation is largely eliminated by deletion of αTAT1, we propose that acetylated microtubules regulate contact inhibition of proliferation through the Hippo pathway.

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Characterizing New Genes Regulating Cell-Substrate Adhesion to Discover Novel Regulatory Mechanisms of Cell Motility

Biophysical Journal ◽

10.1016/j.bpj.2014.11.2488 ◽

2015 ◽

Vol 108 (2) ◽

pp. 456a

Author(s):

Thomas J. Lampert ◽

Peter N. Devreotes

Keyword(s):

Cell Motility ◽

Regulatory Mechanisms ◽

Substrate Adhesion ◽

New Genes ◽

Cell Substrate ◽

Cell Substrate Adhesion

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Myoferlin depletion elevates focal adhesion kinase and paxillin phosphorylation and enhances cell-matrix adhesion in breast cancer cells

AJP Cell Physiology ◽

10.1152/ajpcell.00276.2014 ◽

2015 ◽

Vol 308 (8) ◽

pp. C642-C649 ◽

Cited By ~ 11

Author(s):

B. N. Blackstone ◽

R. Li ◽

W. E. Ackerman ◽

S. N. Ghadiali ◽

H. M. Powell ◽

...

Keyword(s):

Breast Cancer ◽

Focal Adhesion Kinase ◽

Cancer Cells ◽

Breast Cancer Cell ◽

Focal Adhesion ◽

Breast Cancer Cells ◽

Focal Adhesions ◽

Substrate Adhesion ◽

Cell Substrate ◽

Cell Substrate Adhesion

Breast cancer is the second leading cause of malignant death among women. A crucial feature of metastatic cancers is their propensity to lose adhesion to the underlying basement membrane as they transition to a motile phenotype and invade surrounding tissue. Attachment to the extracellular matrix is mediated by a complex of adhesion proteins, including integrins, signaling molecules, actin and actin-binding proteins, and scaffolding proteins. Focal adhesion kinase (FAK) is pivotal for the organization of focal contacts and maturation into focal adhesions, and disruption of this process is a hallmark of early cancer invasive potential. Our recent work has revealed that myoferlin (MYOF) mediates breast tumor cell motility and invasive phenotype. In this study we demonstrate that noninvasive breast cancer cell lines exhibit increased cell-substrate adhesion and that silencing of MYOF using RNAi in the highly invasive human breast cancer cell line MDA-MB-231 also enhances cell-substrate adhesion. In addition, we detected elevated tyrosine phosphorylation of FAK (FAKY397) and paxillin (PAXY118), markers of focal adhesion protein activation. Morphometric analysis of PAX expression revealed that RNAi-mediated depletion of MYOF resulted in larger, more elongated focal adhesions, in contrast to cells transduced with a control virus (MDA-231LVC cells), which exhibited smaller focal contacts. Finally, MYOF silencing in MDA-MB-231 cells exhibited a more elaborate ventral cytoskeletal structure near focal adhesions, typified by pronounced actin stress fibers. These data support the hypothesis that MYOF regulates cell adhesions and cell-substrate adhesion strength and may account for the high degree of motility in invasive breast cancer cells.

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Extracellular signalling modulates Scar/WAVE complex activity through Abi phosphorylation

10.1101/2021.10.09.462405 ◽

2021 ◽

Author(s):

Shashi Prakash Singh ◽

Peter Thomason ◽

Robert Insall

Keyword(s):

Cell Migration ◽

Environmental Cues ◽

Complex Activity ◽

Extracellular Signals ◽

Substrate Adhesion ◽

Cell Substrate ◽

Environmental Responses ◽

Cell Substrate Adhesion ◽

Extracellular Signalling ◽

Wave Complex

The lamellipodia and pseudopodia of migrating cells are produced and maintained by the Scar/WAVE complex. Thus, actin-based cell migration is largely controlled through regulation of Scar/WAVE. Here we report that the Abi subunit - not Scar/WAVE - is phosphorylated in response to extracellular signalling. Like Scar, Abi is phosphorylated after the complex has been activated, implying that Abi phosphorylation modulates pseudopodia, rather than causing new ones to be made. Consistent with this, Scar/WAVE complex mutants that cannot bind Rac are also not phosphorylated. Several environmental cues also affect Abi phosphorylation - cell-substrate adhesion promotes it and increased extracellular osmolarity diminishes it. Both unphosphorylatable and phosphomimetic Abi efficiently rescue the chemotaxis of Abi KO cells and pseudopodia formation, confirming that Abi phosphorylation is not required for activation or inactivation of the Scar/WAVE complex. However, pseudopodia and Scar/WAVE patches in the cells with unphosphorylatable Abi protrude for longer, altering pseudopod dynamics and cell speed. Cells in which Scar and Abi are both unphosphorylatable can still form pseudopods, but migrate substantially faster. We conclude that extracellular signals and environmental responses modulate cell migration by tuning the behaviour of the Scar/WAVE complex after it has been activated.

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A New Member of the Rho Family, Rnd1, Promotes Disassembly of Actin Filament Structures and Loss of Cell Adhesion

The Journal of Cell Biology ◽

10.1083/jcb.141.1.187 ◽

1998 ◽

Vol 141 (1) ◽

pp. 187-197 ◽

Cited By ~ 246

Author(s):

Catherine D. Nobes ◽

Inger Lauritzen ◽

Marie-Geneviève Mattei ◽

Sonia Paris ◽

Alan Hall ◽

...

Keyword(s):

Cell Adhesion ◽

Actin Cytoskeleton ◽

Rho Gtpase ◽

Focal Adhesions ◽

Substrate Adhesion ◽

Cell Substrate ◽

Rho Family ◽

Cell Substrate Adhesion ◽

Distinct Branch

Members of the Rho GTPase family regulate the organization of the actin cytoskeleton in response to extracellular growth factors. We have identified three proteins that form a distinct branch of the Rho family: Rnd1, expressed mostly in brain and liver; Rnd2, highly expressed in testis; and Rnd3/RhoE, showing a ubiquitous low expression. At the subcellular level, Rnd1 is concentrated at adherens junctions both in confluent fibroblasts and in epithelial cells. Rnd1 has a low affinity for GDP and spontaneously exchanges nucleotide rapidly in a physiological buffer. Furthermore, Rnd1 lacks intrinsic GTPase activity suggesting that in vivo, it might be constitutively in a GTP-bound form. Expression of Rnd1 or Rnd3/RhoE in fibroblasts inhibits the formation of actin stress fibers, membrane ruffles, and integrin-based focal adhesions and induces loss of cell–substrate adhesion leading to cell rounding (hence Rnd for “round”). We suggest that these proteins control rearrangements of the actin cytoskeleton and changes in cell adhesion.

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