scholarly journals Substrate rigidity modulates traction forces and stoichiometry of cell matrix adhesions.

2021 ◽  
Author(s):  
Hayri E Balcioglu ◽  
Rolf Harkes ◽  
Erik Danen ◽  
Thomas Schmidt
Keyword(s):  
Intracellular Signaling ◽  
Traction Force ◽  
Effective Stiffness ◽  
Traction Forces ◽  
Superresolution Microscopy ◽  
Cell Matrix ◽  
Force Increase ◽  
Distinct Cell ◽  
Associated Proteins ◽  
Relative Change

In cell matrix adhesions, integrin receptors and associated proteins provide a dynamic coupling of the extracellular matrix (ECM) to the cytoskeleton. This allows bidirectional transmission of forces between the ECM and the cytoskeleton, which tunes intracellular signaling cascades that control survival, proliferation, differentiation, and motility. The quantitative relationships between recruitment of distinct cell matrix adhesion proteins and local cellular traction forces are not known. Here, we applied quantitative superresolution microscopy to cell matrix adhesions formed on fibronectin-stamped elastomeric pillars and developed an approach to relate the number of talin, vinculin, paxillin, and focal adhesion kinase (FAK) molecules to the local cellular traction force. We find that FAK recruitment does not show an association with traction-force application whereas a ~60 pN force increase is associated with the recruitment of one talin, two vinculin, and two paxillin molecules on a substrate of effective stiffness of 47 kPa. On a substrate with a four-fold lower effective stiffness the stoichiometry of talin:vinculin:paxillin changes to 2:12:6 for the same ~60 pN traction force. The relative change in force-related vinculin recruitment indicates a stiffness-dependent switch in vinculin function in cell matrix adhesions. Our results reveal a substrate-stiffness-dependent modulation of the relation between cellular traction-force and the molecular stoichiometry of cell-matrix adhesions.

scholarly journals Vinculin-dependent actin bundling regulates cell migration and traction forces

2015 ◽  
Vol 465 (3) ◽  
pp. 383-393 ◽  
Author(s):  
Karry M. Jannie ◽  
Shawn M. Ellerbroek ◽  
Dennis W. Zhou ◽  
Sophia Chen ◽  
David J. Crompton ◽  
...  
Keyword(s):  
Cell Migration ◽  
Traction Force ◽  
Force Generation ◽  
Actin Binding ◽  
Traction Forces ◽  
Cell Matrix ◽  
Cell Cell

Vinculin transduces force and orchestrates mechanical signalling at cell–cell and cell–matrix adhesions. Cells expressing a mutant vinculin deficient in actin binding and bundling display migration and traction force defects. Vinculin binding to actin is critical for cell migration and force generation.

scholarly journals Dissipation of contractile forces: the missing piece in cell mechanics

2017 ◽  
Vol 28 (14) ◽  
pp. 1825-1832 ◽  
Author(s):  
Laetitia Kurzawa ◽  
Benoit Vianay ◽  
Fabrice Senger ◽  
Timothée Vignaud ◽  
Laurent Blanchoin ◽  
...  
Keyword(s):  
Cell Mechanics ◽  
Force Production ◽  
Traction Force ◽  
Structural Rearrangements ◽  
Force Transmission ◽  
Traction Forces ◽  
Cell Traction Forces ◽  
Cell Traction ◽  
Contractile Forces ◽  
Fiber Contraction

Mechanical forces are key regulators of cell and tissue physiology. The basic molecular mechanism of fiber contraction by the sliding of actin filament upon myosin leading to conformational change has been known for decades. The regulation of force generation at the level of the cell, however, is still far from elucidated. Indeed, the magnitude of cell traction forces on the underlying extracellular matrix in culture is almost impossible to predict or experimentally control. The considerable variability in measurements of cell-traction forces indicates that they may not be the optimal readout to properly characterize cell contractile state and that a significant part of the contractile energy is not transferred to cell anchorage but instead is involved in actin network dynamics. Here we discuss the experimental, numerical, and biological parameters that may be responsible for the variability in traction force production. We argue that limiting these sources of variability and investigating the dissipation of mechanical work that occurs with structural rearrangements and the disengagement of force transmission is key for further understanding of cell mechanics.

scholarly journals Transmission of growth cone traction force through apCAM–cytoskeletal linkages is regulated by Src family tyrosine kinase activity

2001 ◽  
Vol 155 (3) ◽  
pp. 427-438 ◽  
Author(s):  
Daniel M. Suter ◽  
Paul Forscher
Keyword(s):  
Tyrosine Kinase ◽  
Growth Cone ◽  
Kinase Activity ◽  
Kinase Inhibitors ◽  
Traction Force ◽  
Tyrosine Kinase Activity ◽  
Cellular Mechanisms ◽  
Traction Forces ◽  
Kinase Activation ◽  
Neuronal Growth Cone

Tyrosine kinase activity is known to be important in neuronal growth cone guidance. However, underlying cellular mechanisms are largely unclear. Here, we report how Src family tyrosine kinase activity controls apCAM-mediated growth cone steering by regulating the transmission of traction forces through receptor–cytoskeletal linkages. Increased levels of tyrosine phosphorylation were detected at sites where beads coated with apCAM ligands were physically restrained to induce growth cone steering, but not at unrestrained bead binding sites. Interestingly, the rate and level of phosphotyrosine buildup near restrained beads were decreased by the myosin inhibitor 2,3-butanedione-2-monoxime, suggesting that tension promotes tyrosine kinase activation. While not affecting retrograde F-actin flow rates, genistein and the Src family selective tyrosine kinase inhibitors PP1 and PP2 strongly reduced the growth cone's ability to apply traction forces through apCAM–cytoskeletal linkages, assessed using the restrained bead interaction assay. Furthermore, increased levels of an activated Src family kinase were detected at restrained bead sites during growth cone steering events. Our results suggest a mechanism by which growth cones select pathways by sampling both the molecular nature of the substrate and its ability to withstand the application of traction forces.

Study of Cellular Adhesion by Means of Micropillar Surface Topologies

2011 ◽  
Vol 409 ◽  
pp. 105-110 ◽  
Author(s):  
Francesca Boccafoschi ◽  
Marco Rasponi ◽  
Cecilia Mosca ◽  
Erica Bocchi ◽  
Simone Vesentini
Keyword(s):  
Focal Adhesion ◽  
Vascular Tissue ◽  
Focal Adhesions ◽  
Traction Force ◽  
Cellular Adhesion ◽  
Research Field ◽  
Traction Forces ◽  
Adhesion Sites ◽  
Substrate Rigidity ◽  
Open Question

It is well-known that cellular behavior can be guided by chemical signals and physical interactions at the cell-substrate interface. The patterns that cells encounter in their natural environment include nanometer-to-micrometer-sized topographies comprising extracellular matrix, proteins, and adjacent cells. Whether cells transduce substrate rigidity at the microscopic scale (for example, sensing the rigidity between adhesion sites) or the nanoscopic scale remains an open question. Here we report that micromolded elastomeric micropost arrays can decouple substrate rigidity from adhesive and surface properties. Arrays of poly (dimethylsiloxane) (PDMS) microposts from microfabricated silicon masters have been fabricated. To control substrate rigidity they present the same post heights but different surface area and spacing between posts. The main advantage of micropost arrays over other surface modification solutions (i.e. hydrogels) is that measured subcellular traction forces could be attributed directly to focal adhesions. This would allow to map traction forces to individual focal adhesions and spatially quantify subcellular distributions of focal-adhesion area, traction force and focal-adhesion stress. Moreover, different adhesion intracellular pathways could be used by the cells to differentiate toward a proliferative or a contractile cellular phenotype, for instance. This particular application is advantageous for vascular tissue engineering applications, where mimicking as close as possible the vessels dynamics should be a step forward in this research field.

scholarly journals Phase separation and clustering of an ABC transporter in Mycobacterium tuberculosis

2019 ◽  
Vol 116 (33) ◽  
pp. 16326-16331 ◽  
Author(s):  
Florian Heinkel ◽  
Libin Abraham ◽  
Mary Ko ◽  
Joseph Chao ◽  
Horacio Bach ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Phase Separation ◽  
Lipid Bilayers ◽  
Abc Transporter ◽  
Single Molecule ◽  
Intracellular Signaling ◽  
Intrinsically Disordered ◽  
Regulatory Module ◽  
Condensate Formation ◽  
Associated Proteins

Phase separation drives numerous cellular processes, ranging from the formation of membrane-less organelles to the cooperative assembly of signaling proteins. Features such as multivalency and intrinsic disorder that enable condensate formation are found not only in cytosolic and nuclear proteins, but also in membrane-associated proteins. The ABC transporter Rv1747, which is important for Mycobacterium tuberculosis (Mtb) growth in infected hosts, has a cytoplasmic regulatory module consisting of 2 phosphothreonine-binding Forkhead-associated domains joined by an intrinsically disordered linker with multiple phospho-acceptor threonines. Here we demonstrate that the regulatory modules of Rv1747 and its homolog in Mycobacterium smegmatis form liquid-like condensates as a function of concentration and phosphorylation. The serine/threonine kinases and sole phosphatase of Mtb tune phosphorylation-enhanced phase separation and differentially colocalize with the resulting condensates. The Rv1747 regulatory module also phase-separates on supported lipid bilayers and forms dynamic foci when expressed heterologously in live yeast and M. smegmatis cells. Consistent with these observations, single-molecule localization microscopy reveals that the endogenous Mtb transporter forms higher-order clusters within the Mycobacterium membrane. Collectively, these data suggest a key role for phase separation in the function of these mycobacterial ABC transporters and their regulation via intracellular signaling.

scholarly journals Tau tubulin kinase is required for spermatogenesis and development of motile cilia in planarian flatworms

2019 ◽  
Vol 30 (17) ◽  
pp. 2155-2170 ◽  
Author(s):  
Robert Alan Magley ◽  
Labib Rouhana
Keyword(s):  
Intracellular Signaling ◽  
Primary Cilia ◽  
Testicular Tissue ◽  
Structural Defects ◽  
Apical Surface ◽  
Transmission Electron ◽  
Sperm Development ◽  
Associated Proteins ◽  
Motile Cilia ◽  
Reproductive Processes

Cilia are microtubule-based structures that protrude from the apical surface of cells to mediate motility, transport, intracellular signaling, and environmental sensing. Tau tubulin kinases (TTBKs) destabilize microtubules by phosphorylating microtubule-associated proteins (MAPs) of the MAP2/Tau family, but also contribute to the assembly of primary cilia during embryogenesis. Expression of TTBKs is enriched in testicular tissue, but their relevance to reproductive processes is unknown. We identified six TTBK homologues in the genome of the planarian Schmidtea mediterranea ( Smed-TTBK-a, -b, -c, -d, -e, and -f), all of which are preferentially expressed in testes. Inhibition of TTBK paralogues by RNA interference (RNAi) revealed a specific requirement for Smed-TTBK-d in postmeiotic regulation of spermatogenesis. Disrupting expression of Smed-TTBK-d results in loss of spermatozoa, but not spermatids. In the soma, Smed-TTBK-d RNAi impaired the function of multiciliated epidermal cells in propelling planarian movement, as well as the osmoregulatory function of protonephridia. Decreased density and structural defects of motile cilia were observed in the epidermis of Smed-TTBK-d(RNAi) by phase contrast, immunofluorescence, and transmission electron microscopy. Altogether, these results demonstrate that members of the TTBK family of proteins are postmeiotic regulators of sperm development and also contribute to the formation of motile cilia in the soma.

Cross Talk between Cell–Cell and Cell–Matrix Adhesion Signaling Pathways during Heart Organogenesis: Implications for Cardiac Birth Defects

2005 ◽  
Vol 11 (3) ◽  
pp. 200-208 ◽  
Author(s):  
Kersti K. Linask ◽  
Shyam Manisastry ◽  
Mingda Han
Keyword(s):  
Signaling Pathways ◽  
Cross Talk ◽  
Intracellular Signaling ◽  
Heart Defects ◽  
Short Interval ◽  
Regulation Of Gene Expression ◽  
Calcium Dependent ◽  
Form And Function ◽  
Cell Matrix ◽  
Anterior Posterior

The anterior–posterior and dorsal–ventral progression of heart organogenesis is well illustrated by the patterning and activity of two members of different families of cell adhesion molecules: the calcium-dependent cadherins, specifically N-cadherin, and the extracellular matrix glycoproteins, fibronectin. N-cadherin by its binding to the intracellular molecule β-catenin and fibronectin by its binding to integrins at focal adhesion sites, are involved in regulation of gene expression by their association with the cytoskeleton and through signal transduction pathways. The ventral precardiac mesoderm cells epithelialize and become stably committed by the activation of these cell–matrix and intracellular signaling transduction pathways. Cross talk between the adhesion signaling pathways initiates the characteristic phenotypic changes associated with cardiomyocyte differentiation: electrical activity and organization of myofibrils. The development of both organ form and function occurs within a short interval thereafter. Mutations in any of the interacting molecules, or environmental insults affecting either of these signaling pathways, can result in embryonic lethality or fetuses born with severe heart defects. As an example, we have defined that exposure of the embryo temporally to lithium during an early sensitive developmental period affects a canonical Wnt pathway leading to β-catenin stabilization. Lithium exposure results in an anterior–posterior progression of severe cardiac defects.

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