Biochemical Purification of Pseudopodia from Migratory Cells

2007 ◽  
pp. 55-66 ◽  
Author(s):  
Yingchun Wang ◽  
Richard L. Klemke
Keyword(s):  
Biochemical Purification ◽  
Migratory Cells

Biochemical Purification of Pseudopodia from Migratory Cells

2007 ◽  
pp. 55-66
Author(s):  
Yingchun Wang ◽  
Richard L. Klemke
Keyword(s):  
Biochemical Purification ◽  
Migratory Cells

scholarly journals Protein kinase C regulates the recruitment of syndecan-4 into focal contacts.

1995 ◽  
Vol 6 (11) ◽  
pp. 1503-1513 ◽  
Author(s):  
P C Baciu ◽  
P F Goetinck
Keyword(s):  
Protein Kinase C ◽  
Cell Adhesion ◽  
Protein Kinase ◽  
Heparan Sulfate ◽  
Heparan Sulfate Proteoglycans ◽  
Matrix Deposition ◽  
Kinase C ◽  
Focal Contacts ◽  
The Matrix ◽  
Migratory Cells

Cell surface heparan sulfate proteoglycans have been implicated as co-receptors facilitating cell adhesion and growth factor binding. Recent studies on the role of a family of transmembrane heparan sulfate proteoglycans, syndecans, in cell adhesion has identified one member, syndecan-4, to be present within focal contacts. The current study investigates the mechanisms regulating the association of syndecan-4 with focal contacts based upon its immunolocalization with vinculin in quiescent, serum-stimulated, and 12-0-tetradecanoylphorbol 13-acetate (TPA)-induced cultures. In quiescent cells, syndecan-4 did not localize to focal contacts. However, activation of protein kinase C by TPA or serum induces the active recruitment of syndecan-4 into focal contacts. This induction preferentially localizes syndecan-4 to focal contacts behind the leading lamella, the subnuclear region, and along the trailing edge of migratory cells. Focal contacts in either freshly adhered cells or in the leading lamellae of migrating cells did not stain for syndecan-4. In addition to the observed subcellular distribution and recruitment, syndecan-4 was observed to co-localize with endogenously synthesized fibronectin fibrils within focal contacts as well as with fibrils present in the matrix. These findings suggest that protein kinase C activation results in syndecan-4 recruitment to focal contacts and its association with sites of matrix deposition.

Overexpression of Snail family members highlights their ability to promote chick neural crest formation

Development ◽  
2002 ◽  
Vol 129 (7) ◽  
pp. 1583-1593 ◽  
Author(s):  
Marta G. del Barrio ◽  
M. Angela Nieto
Keyword(s):  
Chick Embryo ◽  
Neural Crest ◽  
Neural Tube ◽  
Family Members ◽  
Ectopic Expression ◽  
Endogenous Gene ◽  
The Family ◽  
Snail Family ◽  
Migratory Cells ◽  
Snail Gene

The Snail gene family of transcription factors plays crucial roles in different morphogenetic processes during the development of vertebrate and invertebrate embryos. In previous studies of function interference for one of the family members, Slug, we showed its involvement and neural crest formation in the chick embryo. Now we have carried out a series of gain-of-function experiments in which we show that Slug overexpression in the neural tube of the chick embryo induces an increase in neural crest production. The analysis of electroporated embryos shows that Slug can induce the expression of rhoB and an increase in the number of HNK-1-positive migratory cells, indicating that it lies upstream of them in the genetic cascade of neural crest development. The increase in neural crest production after Slug overexpression was confined to the cranial region, indicating that the mechanisms of crest induction somehow differ between head and trunk. The expression of the two vertebrate family members, Slug and Snail, is peculiar with respect to the neural crest. Slug is not expressed in the premigratory crest in the mouse, whereas it is expressed in this cell population in the chick and the opposite is true for Snail(Sefton, M., Sánchez, S. and Nieto M. A. (1998) Development125, 3111-3121). This raises the question of whether they can be functionally equivalent. To test this hypothesis both intra- and interspecies, we have performed a series of ectopic expression experiments by electroporating chick and mouse Snail in the chick embryo hindbrain. We observe that both genes elicit the same responses in the neural tube. Our results indicate that they can be functionally equivalent, although the embryos show a higher response to the endogenous gene, chick Slug.

scholarly journals R-Ras Controls Membrane Protrusion and Cell Migration through the Spatial Regulation of Rac and Rho

2005 ◽  
Vol 16 (1) ◽  
pp. 84-96 ◽  
Author(s):  
Michele A. Wozniak ◽  
Lina Kwong ◽  
David Chodniewicz ◽  
Richard L. Klemke ◽  
Patricia J. Keely
Keyword(s):  
Cell Migration ◽  
Molecular Mechanisms ◽  
Leading Edge ◽  
Pi3 Kinase ◽  
Dominant Negative ◽  
Cell Periphery ◽  
Membrane Protrusion ◽  
Spatial Regulation ◽  
Entire Cell ◽  
Migratory Cells

Although it is known that the spatial coordination of Rac and Rho activity is essential for cell migration, the molecular mechanisms regulating these GTPases during migration are unknown. We found that the expression of constitutively activated R-Ras (38V) blocked membrane protrusion and random migration. In contrast, expression of dominant negative R-Ras (41A) enhanced migrational persistence and membrane protrusion. Endogenous R-Ras is necessary for cell migration, as cells that were transfected with siRNA for R-Ras did not migrate. Expression of R-Ras (38V) decreased Rac activity and increased Rho activity around the entire cell periphery, whereas expression of dominant negative R-Ras (41A) showed the converse, suggesting that R-Ras can spatially activate Rho and inactivate Rac. Consistent with this role, endogenous R-Ras localized and was preferentially activated at the leading edge of migratory cells in response to adhesion. The effects of R-Ras on cell migration are mediated by PI3-Kinase, as an effector mutant that uncouples PI3-Kinase binding from R-Ras (38V) rescued migration. From these data, we hypothesize that R-Ras plays a key role in cell migration by locally regulating the switch from Rac to Rho activity after membrane protrusion and adhesion.

Protease Crosstalk with Integrins: the Urokinase Receptor Paradigm

2001 ◽  
Vol 86 (07) ◽  
pp. 124-129 ◽  
Author(s):  
Ying Wei ◽  
Harold Chapman
Keyword(s):  
Proteolytic Enzymes ◽  
Src Family Kinases ◽  
Urokinase Receptor ◽  
Integrin Signaling ◽  
Membrane Rafts ◽  
Cell Matrix ◽  
Matrix Interactions ◽  
Cell Matrix Interactions ◽  
Migratory Cells ◽  
Β2 Integrins

SummaryMigratory cells use both adhesion receptors and proteolytic enzymes to regulate their interaction with and response to extracellular matrices. Cooperation between integrins and proteases operates at several levels: integrin signaling induces proteases, proteases co-localize with integrins, and proteases regulate the interface between integrins and the intracellular cytoskeleton. One protease system intimately connected to integrins is the urokinase/urokinase receptor(uPAR)/plasmin system. Recent studies indicate urokinase promotes the ligand-like binding of its receptor to a set of β1 and β2 integrins, this binding in turn affecting integrin signaling and cell migration. The glycolipid anchor of uPAR associates with cholesterol-rich membrane rafts. Binding of uPAR to integrins may enrich integrin clusters with signaling molecules such as src-family kinases that localize to rafts and are important to integrin function. Signals derived from integrin/uPAR complexes promote the function of other integrins. Thus the urokinase/plasmin system coordinates with integrins to regulate cell: matrix interactions.

scholarly journals Expression of the neuropeptide SALMFamide-1 during regeneration of the seastar radial nerve cord following arm autotomy

2019 ◽  
Vol 286 (1901) ◽  
pp. 20182701 ◽  
Author(s):  
Maria Byrne ◽  
Franca Mazzone ◽  
Maurice R. Elphick ◽  
Michael C. Thorndyke ◽  
Paula Cisternas
Keyword(s):  
Wound Healing ◽  
Nervous System ◽  
Nerve Cord ◽  
Radial Nerve ◽  
Model System ◽  
Rapid Recovery ◽  
Nerve Stump ◽  
Rapid Access ◽  
Migratory Cells ◽  
Rapid Appearance

Arm loss through a separation at a specialized autotomy plane in echinoderms is inextricably linked to regeneration, but the link between these phenomena is poorly explored. We investigated nervous system regeneration post-autotomy in the asteriid seastar Coscinasterias muricata , focusing on the reorganization of the radial nerve cord (RNC) into the ectoneural neuroepithelium and neuropile, and the hyponeural region, using antibodies to the seastar-specific neuropeptide SALMFamide-1 (S1). Parallel changes in the associated haemal and coelomic vessels were also examined. A new arm bud appeared in 3–5 days with regeneration over three weeks. At the nerve stump and in the RNC immediately behind, the haemal sinus/hyponeural coelomic compartments enlarged into a hypertrophied space filled with migratory cells that appear to be involved in wound healing and regeneration. The haemal and coelomic compartments provided a conduit for these cells to gain rapid access to the regeneration site. An increase in the number of glia-like cells indicates the importance of these cells in regeneration. Proximal to the autotomy plane, the original RNC exhibited Wallerian-type degeneration, as seen in disorganized axons and enlarged S1-positive varicosities. The imperative to regrow lost arms quickly is reflected in the efficiency of regeneration from the autotomy plane facilitated by the rapid appearance of progenitor-like migratory cells. In parallel to its specialization for defensive arm detachment, the autotomy plane appears to be adapted to promote regeneration. This highlights the importance of examining autotomy-induced regeneration in seastars as a model system to study nervous system regeneration in deuterostomes and the mechanisms involved with the massive migration of stem-like cells to facilitate rapid recovery.

scholarly journals LKB1 specifies neural crest cell fates through pyruvate-alanine cycling

2019 ◽  
Vol 5 (7) ◽  
pp. eaau5106 ◽  
Author(s):  
Anca G. Radu ◽  
Sakina Torch ◽  
Florence Fauvelle ◽  
Karin Pernet-Gallay ◽  
Anthony Lucas ◽  
...  
Keyword(s):  
Neural Crest ◽  
Cell Fate ◽  
Neural Crest Cell ◽  
Dependent Manner ◽  
Cell Fates ◽  
Neural Crest Stem Cells ◽  
Metabolomic Profiling ◽  
Intestinal Pseudo Obstruction ◽  
Migratory Cells ◽  
Hind Limb Paralysis

Metabolic processes underlying the development of the neural crest, an embryonic population of multipotent migratory cells, are poorly understood. Here, we report that conditional ablation of the Lkb1 tumor suppressor kinase in mouse neural crest stem cells led to intestinal pseudo-obstruction and hind limb paralysis. This phenotype originated from a postnatal degeneration of the enteric nervous ganglia and from a defective differentiation of Schwann cells. Metabolomic profiling revealed that pyruvate-alanine conversion is enhanced in the absence of Lkb1. Mechanistically, inhibition of alanine transaminases restored glial differentiation in an mTOR-dependent manner, while increased alanine level directly inhibited the glial commitment of neural crest cells. Treatment with the metabolic modulator AICAR suppressed mTOR signaling and prevented Schwann cell and enteric defects of Lkb1 mutant mice. These data uncover a link between pyruvate-alanine cycling and the specification of glial cell fate with potential implications in the understanding of the molecular pathogenesis of neural crest diseases.

scholarly journals FAK signaling is critical for ErbB-2/ErbB-3 receptor cooperation for oncogenic transformation and invasion

2005 ◽  
Vol 171 (3) ◽  
pp. 505-516 ◽  
Author(s):  
Naciba Benlimame ◽  
Qiang He ◽  
Su Jie ◽  
Dingzhang Xiao ◽  
Ying Jie Xu ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Cell Invasion ◽  
Cell Transformation ◽  
Mitogen Activated Protein Kinase ◽  
Tyrosine Kinase Receptor ◽  
Oncogenic Transformation ◽  
Mitogen Activated Protein ◽  
Migratory Cells

The overexpression of members of the ErbB tyrosine kinase receptor family has been associated with cancer progression. We demonstrate that focal adhesion kinase (FAK) is essential for oncogenic transformation and cell invasion that is induced by ErbB-2 and -3 receptor signaling. ErbB-2/3 overexpression in FAK-deficient cells fails to promote cell transformation and rescue chemotaxis deficiency. Restoration of FAK rescues both oncogenic transformation and invasion that is induced by ErbB-2/3 in vitro and in vivo. In contrast, the inhibition of FAK in FAK-proficient invasive cancer cells prevented cell invasion and metastasis formation. The activation of ErbB-2/3 regulates FAK phosphorylation at Tyr-397, -861, and -925. ErbB-induced oncogenic transformation correlates with the ability of FAK to restore ErbB-2/3–induced mitogen-activated protein kinase (MAPK) activation; the inhibition of MAPK prevented oncogenic transformation. In contrast, the inhibition of Src but not MAPK prevented ErbB–FAK-induced chemotaxis. In migratory cells, activated ErbB-2/3 receptors colocalize with activated FAK at cell protrusions. This colocalization requires intact FAK. In summary, distinct FAK signaling has an essential function in ErbB-induced oncogenesis and invasiveness.

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