Faculty Opinions recommendation of Light-mediated activation reveals a key role for Rac in collective guidance of cell movement in vivo.

2010 ◽  
Author(s):  
Jonathan Chernoff
Keyword(s):  
Cell Movement

scholarly journals Mechanisms responsible for F-actin stabilization after lysis of polymorphonuclear leukocytes.

1992 ◽  
Vol 116 (5) ◽  
pp. 1123-1134 ◽  
Author(s):  
M L Cano ◽  
L Cassimeris ◽  
M Fechheimer ◽  
S H Zigmond
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Actin Polymerization ◽  
Cell Movement ◽  
Actin Binding ◽  
Cross Linking ◽  
Macromolecular Complex ◽  
Actin Depolymerization ◽  
Gravitational Forces ◽  
End Capping

While actin polymerization and depolymerization are both essential for cell movement, few studies have focused on actin depolymerization. In vivo, depolymerization can occur exceedingly rapidly and in a spatially defined manner: the F-actin in the lamellipodia depolymerizes in 30 s after chemoattractant removal (Cassimeris, L., H. McNeill, and S. H. Zigmond. 1990. J. Cell Biol. 110:1067-1075). To begin to understand the regulation of F-actin depolymerization, we have examined F-actin depolymerization in lysates of polymorphonuclear leukocytes (PMNs). Surprisingly, much of the cell F-actin, measured with a TRITC-phalloidin-binding assay, was stable after lysis in a physiological salt buffer (0.15 M KCl): approximately 50% of the F-actin did not depolymerize even after 18 h. This stable F-actin included lamellar F-actin which could still be visualized one hour after lysis by staining with TRITC-phalloidin and by EM. We investigated the basis for this stability. In lysates with cell concentrations greater than 10(7) cells/ml, sufficient globular actin (G-actin) was present to result in a net increase in F-actin. However, the F-actin stability was not solely because of the presence of free G-actin since addition of DNase I to the lysate did not increase the F-actin loss. Nor did it appear to be because of barbed end capping factors since cell lysates provided sites for barbed end polymerization of exogenous added actin. The stable F-actin existed in a macromolecular complex that pelleted at low gravitational forces. Increasing the salt concentration of the lysis buffer decreased the amount of F-actin that pelleted at low gravitational forces and increased the amount of F-actin that depolymerized. Various actin-binding and cross-linking proteins such as tropomyosin, alpha-actinin, and actin-binding protein pelleted with the stable F-actin. In addition, we found that alpha-actinin, a filament cross-linking protein, inhibited the rate of pyrenyl F-actin depolymerization. These results suggested that actin cross-linking proteins may contribute to the stability of cellular actin after lysis. The activity of crosslinkers may be regulated in vivo to allow rapid turnover of lamellipodia F-actin.

The mechanism of mouse egg-cylinder morphogenesis in vitro

Development ◽  
1981 ◽  
Vol 61 (1) ◽  
pp. 277-287
Author(s):  
A. J. Copp
Keyword(s):  
Giant Cell ◽  
Cell Formation ◽  
Cell Movement ◽  
Giant Cells ◽  
Cell Number ◽  
Dependent Change ◽  
Morphogenesis In Vitro ◽  
Trophoblast Giant Cells

The number of trophoblast giant cells in outgrowths of mouse blastocysts was determined before, during and after egg-cylinder formation in vitro. Giant-cell numbers rose initially but reached a plateau 12 h before the egg cylinder appeared. A secondary increase began 24 h after egg-cylinder formation. Blastocysts whose mural trophectoderm cells were removed before or shortly after attachment in vitro formed egg cylinders at the same time as intact blastocysts but their trophoblast outgrowths contained fewer giant cells at this time. The results support the idea that egg-cylinder formation in vitro is accompanied by a redirection of the polar to mural trophectoderm cell movement which characterizes blastocysts before implantation. The resumption of giant-cell number increase in trophoblast outgrowths after egg-cylinder formation may correspond to secondary giant-cell formation in vivo. It is suggested that a time-dependent change in the strength of trophoblast cell adhesion to the substratum occurs after blastocyst attachment in vitro which restricts the further entry of polar cells into the outgrowth and therefore results in egg-cylinder formation.

scholarly journals Smurf1 regulates tumor cell plasticity and motility through degradation of RhoA leading to localized inhibition of contractility

2006 ◽  
Vol 176 (1) ◽  
pp. 35-42 ◽  
Author(s):  
Erik Sahai ◽  
Raquel Garcia-Medina ◽  
Jacques Pouysségur ◽  
Emmanuel Vial
Keyword(s):  
Cell Migration ◽  
Tumor Cell ◽  
Rho Gtpases ◽  
Rho Kinase ◽  
Cell Movement ◽  
Leading Edge ◽  
Cell Periphery ◽  
Tumor Cell Migration ◽  
Tumor Cell Motility

Rho GTPases participate in various cellular processes, including normal and tumor cell migration. It has been reported that RhoA is targeted for degradation at the leading edge of migrating cells by the E3 ubiquitin ligase Smurf1, and that this is required for the formation of protrusions. We report that Smurf1-dependent RhoA degradation in tumor cells results in the down-regulation of Rho kinase (ROCK) activity and myosin light chain 2 (MLC2) phosphorylation at the cell periphery. The localized inhibition of contractile forces is necessary for the formation of lamellipodia and for tumor cell motility in 2D tissue culture assays. In 3D invasion assays, and in in vivo tumor cell migration, the inhibition of Smurf1 induces a mesenchymal–amoeboid–like transition that is associated with a more invasive phenotype. Our results suggest that Smurf1 is a pivotal regulator of tumor cell movement through its regulation of RhoA signaling.

scholarly journals An In Vitro Model for Assessing Corneal Keratocyte Spreading and Migration on Aligned Fibrillar Collagen

2018 ◽  
Vol 9 (4) ◽  
pp. 54 ◽  
Author(s):  
Pouriska Kivanany ◽  
Kyle Grose ◽  
Nihan Yonet-Tanyeri ◽  
Sujal Manohar ◽  
Yukta Sunkara ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Cell Movement ◽  
Time Lapse ◽  
Collagen Fibrils ◽  
Fibrillar Collagen ◽  
Freeze Injury

Background: Corneal stromal cells (keratocytes) are responsible for developing and maintaining normal corneal structure and transparency, and for repairing the tissue after injury. Corneal keratocytes reside between highly aligned collagen lamellae in vivo. In addition to growth factors and other soluble biochemical factors, feedback from the extracellular matrix (ECM) itself has been shown to modulate corneal keratocyte behavior. Methods: In this study, we fabricate aligned collagen substrates using a microfluidics approach and assess their impact on corneal keratocyte morphology, cytoskeletal organization, and patterning after stimulation with platelet derived growth factor (PDGF) or transforming growth factor beta 1 (TGFβ). We also use time-lapse imaging to visualize the dynamic interactions between cells and fibrillar collagen during wound repopulation following an in vitro freeze injury. Results: Significant co-alignment between keratocytes and aligned collagen fibrils was detected, and the degree of cell/ECM co-alignment further increased in the presence of PDGF or TGFβ. Freeze injury produced an area of cell death without disrupting the collagen. High magnification, time-lapse differential interference contrast (DIC) imaging allowed cell movement and subcellular interactions with the underlying collagen fibrils to be directly visualized. Conclusions: With continued development, this experimental model could be an important tool for accessing how the integration of multiple biophysical and biochemical signals regulate corneal keratocyte differentiation.

scholarly journals Self-organized cell migration across scales – from single cell movement to tissue formation

Development ◽  
2021 ◽  
Vol 148 (7) ◽  
pp. dev191767
Author(s):  
Jessica Stock ◽  
Andrea Pauli
Keyword(s):  
Cell Migration ◽  
Multiple Scales ◽  
Single Cells ◽  
Cell Movement ◽  
Biological Response ◽  
Collective Cell Migration ◽  
Theoretical Concepts ◽  
Self Organizing

ABSTRACTSelf-organization is a key feature of many biological and developmental processes, including cell migration. Although cell migration has traditionally been viewed as a biological response to extrinsic signals, advances within the past two decades have highlighted the importance of intrinsic self-organizing properties to direct cell migration on multiple scales. In this Review, we will explore self-organizing mechanisms that lay the foundation for both single and collective cell migration. Based on in vitro and in vivo examples, we will discuss theoretical concepts that underlie the persistent migration of single cells in the absence of directional guidance cues, and the formation of an autonomous cell collective that drives coordinated migration. Finally, we highlight the general implications of self-organizing principles guiding cell migration for biological and medical research.

scholarly journals DAAM mediates the assembly of long-lived, treadmilling stress fibers in collectively migrating epithelial cells in Drosophila

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Kristin M Sherrard ◽  
Maureen Cetera ◽  
Sally Horne-Badovinac
Keyword(s):  
Epithelial Cells ◽  
Cell Movement ◽  
Stress Fibers ◽  
Linear Trajectory ◽  
Epithelial Migration ◽  
Cells In Culture ◽  
Multiple Cell ◽  
Developmental Switch ◽  
Over Time

Stress fibers (SFs) are actomyosin bundles commonly found in individually migrating cells in culture. However, whether and how cells use SFs to migrate in vivo or collectively is largely unknown. Studying the collective migration of the follicular epithelial cells in Drosophila, we found that the SFs in these cells show a novel treadmilling behavior that allows them to persist as the cells migrate over multiple cell lengths. Treadmilling SFs grow at their fronts by adding new integrin-based adhesions and actomyosin segments over time. This causes the SFs to have many internal adhesions along their lengths, instead of adhesions only at the ends. The front-forming adhesions remain stationary relative to the substrate and typically disassemble as the cell rear approaches. By contrast, a different type of adhesion forms at the SF’s terminus that slides with the cell’s trailing edge as the actomyosin ahead of it shortens. We further show that SF treadmilling depends on cell movement and identify a developmental switch in the formins that mediate SF assembly, with Dishevelled-associated activator of morphogenesis acting during migratory stages and Diaphanous acting during postmigratory stages. We propose that treadmilling SFs keep each cell on a linear trajectory, thereby promoting the collective motility required for epithelial migration.

Teleost epiboly: a reassessment of deep cell movement in the germ ring

Development ◽  
1988 ◽  
Vol 102 (3) ◽  
pp. 575-585 ◽  
Author(s):  
A. Wood ◽  
L.P.M. Timmermans
Keyword(s):  
Direct Evidence ◽  
Cell Layer ◽  
Cell Movement ◽  
Current View ◽  
Differential Interference Contrast Microscopy ◽  
Nomarski Differential Interference Contrast ◽  
Contrast Microscopy ◽  
Interference Contrast Microscopy ◽  
Intrinsic Marker

Using the prominent cell nucleus as an intrinsic marker, individual deep cell blastomeres have been monitored in vivo using Nomarski differential interference contrast microscopy during spreading of the teleost blastoderm. Involution of these cells has been recorded during early to mid stages of epiboly about an apparent point of shear located centrally within the germ ring. This involuting movement involves superficial deep cells, adjacent to the enveloping layer, as well as those located more centrally within the germ ring and is associated with a continuous vegetal displacement of the outer strata of deep cell blastomeres towards the edge of the blastodisc. During the early stages of epiboly this process is qualitatively similar at any location around the entire circumferential margin of the blastodisc. Postinvoluting deep cells are found close to the yolk syncytial layer, are surrounded by considerable intercellular space and illustrate less directional displacement. In contrast to the deep cell layer, the enveloping layer was never observed to invaginate. These results contradict the current view that no involution or global rearrangement of deep cells occurs during teleost gastrulation and present the first direct evidence of involution within the deep cell population during early epiboly.

Inhibition of leukocyte locomotion by hyaluronic acid

1981 ◽  
Vol 48 (1) ◽  
pp. 315-331
Author(s):  
J.V. Forrester ◽  
P.C. Wilkinson
Keyword(s):  
Molecular Weight ◽  
Visual Analysis ◽  
Cell Movement ◽  
Chemotactic Factor ◽  
Major Constituent ◽  
Dependent Manner ◽  
Surface Binding ◽  
Micropore Filter

The effect of hyaluronate on neutrophil motility in vitro was studied by the micropore filter technique and by direct visual analysis of the locomotion of neutrophils on glass. Both directed and random locomotion of neutrophils was inhibited by physiological concentrations (0.5-6.0 mg ml(−1)) of hyaluronate in a dose- and molecular weight-dependent manner. Inhibition of cell movement was more pronounced for high molecular weight chemoattractants such as casein than for small chemotactic peptides such as f-Met-Leu-Phe. Chemotactic factor gradient formation in filter chambers was profoundly retarded by hyaluronate, which may partly explain the inhibitory effects of hyaluronate on directed neutrophil locomotion. In addition, hyaluronate inhibited the binding of chemotactic factor to the neutrophil surface. This effect, together with a reduction in cell-to-substratum adhesion, may provide an additional explanation for hyaluronate-induced inhibition of random neutrophil locomotion. Inhibition of locomotion by hyaluronate was easily reversed by washing the cells free of hyaluronate; thus competition by hyaluronate for cell-surface binding sites is unlikely, and physical effects such as steric exclusion or molecular sieving by the large hyaluronate polymer provide the most probable explanations of its inhibitory effect on cell locomotion. Since hyaluronate is a major constituent of tissue matrices, these results draw attention to the importance of the extracellular environment in regulating inflammatory cell movement in vivo.

Sign in / Sign up

Export Citation Format

Share Document