scholarly journals uPAR-induced cell adhesion and migration: vitronectin provides the key

2007 ◽  
Vol 177 (5) ◽  
pp. 927-939 ◽  
Author(s):  
Chris D. Madsen ◽  
Gian Maria Sarra Ferraris ◽  
Annapaola Andolfo ◽  
Orla Cunningham ◽  
Nicolai Sidenius
Keyword(s):  
Cell Adhesion ◽  
Protein Interactions ◽  
Cell Morphology ◽  
Plasminogen Activator Inhibitor ◽  
Hek293 Cells ◽  
Molecular Defect ◽  
Plasminogen Activator Inhibitor 1 ◽  
The Matrix ◽  
Cell Adhesion And Migration ◽  
And Migration

Expression of the membrane receptor uPAR induces profound changes in cell morphology and migration, and its expression correlates with the malignant phenotype of cancers. To identify the molecular interactions essential for uPAR function in these processes, we carried out a complete functional alanine scan of uPAR in HEK293 cells. Of the 255 mutant receptors characterized, 34 failed to induce changes in cell morphology. Remarkably, the molecular defect of all of these mutants was a specific reduction in integrin-independent cell binding to vitronectin. A membrane-tethered plasminogen activator inhibitor-1, which has the same binding site in vitronectin as uPAR, replicated uPAR-induced changes. A direct uPAR–vitronectin interaction is thus both required and sufficient to initiate downstream changes in cell morphology, migration, and signal transduction. Collectively these data demonstrate a novel mechanism by which a cell adhesion molecule lacking inherent signaling capability evokes complex cellular responses by modulating the contact between the cell and the matrix without the requirement for direct lateral protein–protein interactions.

Proteolysis, Cell Adhesion, Chemotaxis, and Invasiveness Are Regulated by the u-PA-u-PAR-PAI-1 System

1999 ◽  
Vol 82 (08) ◽  
pp. 298-304 ◽  
Author(s):  
Francesco Blasi
Keyword(s):  
Cell Adhesion ◽  
Plasminogen Activator ◽  
Tyrosine Kinases ◽  
Plasminogen Activator Inhibitor ◽  
Prognostic Indicators ◽  
Type Plasminogen Activator ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Pai 1

IntroductionHigh levels of urokinase-type plasminogen activator (u-PA), of its inhibitor (plasminogen activator inhibitor (PAI)-1), or of its receptor (u-PAR, CD87) are strong prognostic indicators of relapse in human cancers. In addition, many in vitro data show that u-PA, PAI-1, and u-PAR have a profound influence on cell migration. This set of molecules regulates surface proteolysis, cell adhesion, and chemotaxis through different mechanisms. Binding to u-PAR strongly stimulates the activation of pro-u-PA and, hence, of plasminogen, resulting in localized production of the broad-spectrum serine protease, plasmin, which can digest extracellular matrix proteins or activate latent motogenic factors. Chemotaxis is induced through an u-PA-dependent conformational change in u-PAR, which uncovers a very potent chemotactic epitope(s) that acts through a pertussis toxin-sensitive step and activates intracellular tyrosine kinases. In addition, cell adhesion is affected by an u-PA-dependent exposure of u-PAR epitope(s), which interact with vitronectin (VN), integrins, and caveolin, thus modifying the substrate specificity. Thus, u-PA binding can transform u-PAR from a simple receptor for u-PA into a pleiotropic ligand for other surface molecules.All of these processes are regulated by the u-PA inhibitor, PAI-1. Inhibition of cell adhesion and migration by PAI-1 on VN occurs because the same region of VN is required for interaction with PAI-1, u-PAR, and integrins. PAI-1, however, also affects u-PAR occupancy by triggering the internalization of the u-PA-u-PAR complex, the degradation of u-PA, and the recycling of free u-PAR. Available data suggest that cells respond to a “stop” signal, due to the PAI-1-dependent internalization and degradation of u-PA. Cells also respond to a “go” signal through the stimulation of surface-proteolysis, exposure of chemotactic epitopes, and recycling of u-PAR to novel surface positions. Finally, cells respond to a “pause” signal through transient u-PAR-dependent adhesion stages, thus shifting the cells between an “adhesion-mode” and a “migration-mode.”

Ubiquitin links to cytoskeletal dynamics, cell adhesion and migration

2012 ◽  
Vol 442 (1) ◽  
pp. 13-25 ◽  
Author(s):  
Antje Schaefer ◽  
Micha Nethe ◽  
Peter L. Hordijk
Keyword(s):  
Cell Adhesion ◽  
Protein Interactions ◽  
Protein Modification ◽  
Covalent Attachment ◽  
Cellular Functions ◽  
Vesicular Traffic ◽  
Additional Information ◽  
Cytoskeletal Dynamics ◽  
Cell Adhesion And Migration ◽  
And Migration

Post-translational modifications are used by cells to link additional information to proteins. Most modifications are subtle and concern small moieties such as a phosphate group or a lipid. In contrast, protein ubiquitylation entails the covalent attachment of a full-length protein such as ubiquitin. The protein ubiquitylation machinery is remarkably complex, comprising more than 15 Ubls (ubiquitin-like proteins) and several hundreds of ubiquitin-conjugating enzymes. Ubiquitin is best known for its role as a tag that induces protein destruction either by the proteasome or through targeting to lysosomes. However, addition of one or more Ubls also affects vesicular traffic, protein–protein interactions and signal transduction. It is by now well established that ubiquitylation is a component of most, if not all, cellular signalling pathways. Owing to its abundance in controlling cellular functions, ubiquitylation is also of key relevance to human pathologies, including cancer and inflammation. In the present review, we focus on its role in the control of cell adhesion, polarity and directional migration. It will become clear that protein modification by Ubls occurs at every level from the receptors at the plasma membrane down to cytoskeletal components such as actin, with differential consequences for the pathway's final output. Since ubiquitylation is fast as well as reversible, it represents a bona fide signalling event, which is used to fine-tune a cell's responses to receptor agonists.

scholarly journals Lipogenic signalling modulates prostate cancer cell adhesion and migration via modification of Rho GTPases

Oncogene ◽  
2020 ◽  
Vol 39 (18) ◽  
pp. 3666-3679 ◽  
Author(s):  
Mario De Piano ◽  
Valeria Manuelli ◽  
Giorgia Zadra ◽  
Jonathan Otte ◽  
Per-Henrik D. Edqvist ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cell Adhesion ◽  
Cancer Cell ◽  
Rho Gtpases ◽  
Prostate Cancer Cell ◽  
Cancer Cell Adhesion ◽  
Cell Adhesion And Migration ◽  
And Migration

Differences in phosphatase modulation of α4 β1 and α5 β1 integrin-mediated adhesion and migration of B16F1 cells

1999 ◽  
Vol 77 (5) ◽  
pp. 409-420 ◽  
Author(s):  
Dolores Hangan-Steinman ◽  
Wai-chi Ho ◽  
Priti Shenoy ◽  
Bosco MC Chan ◽  
Vincent L Morris
Keyword(s):  
Cell Adhesion ◽  
Adhesive Strength ◽  
Cell Movement ◽  
Protein Tyrosine Phosphatases ◽  
Β1 Integrin ◽  
Phosphatase Inhibitors ◽  
Β1 Integrins ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
B16f1 Cell

It is well established that a biphasic relationship exists between the adhesive strength of β1 integrins and their ability to mediate cell movement. Thus, cell movement increases progressively with adhesive strength, but beyond a certain point of optimal interaction, cell movement is reduced with further increases in adhesive function. The interplay between the various kinase and phosphatase activities provides the balance in β1 integrin-mediated cell adhesion and migration. In the present study, the significance of protein tyrosine phosphatases (PTP) and ser/thr protein phosphatases (PP) in α4β1 and α5β1 integrin-mediated mouse melanoma B16F1 cell anchorage and migration on fibronectin was characterized using phosphatase inhibitors. At low fibronectin concentration, α5β1 functioned as the predominant receptor for cell movement; a role for α4β1 in B16F1 cell migration increased progressively with fibronectin concentration. Treatment of B16F1 cells with PTP inhibitors, sodium orthovanadate (Na3VO4) and phenylarsine oxide (PAO), or PP-1/2A inhibitor, okadaic acid (OA), abolished cell movement. Inhibition of cell movement by PAO and OA was associated by a reduction in the adhesive strength of α4β1 and α5β1. In contrast, treatment of B16F1 cells with Na3VO4 resulted in selective stimulation of the adhesive function of α5β1, but not α4β1. Therefore, our results demonstrate that (i) both PTP and PP-1/2A have roles in cell movement, (ii) modulation of cell movement by PTP and PP-1/2A may involve either a stimulation or reduction of β1 integrin adhesive strength, and (iii) distinct phosphatase-mediated signaling pathways for differential regulation of the various β1 integrins exist. Key words: phosphatases, integrins, cell movement, cell adhesion.

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