scholarly journals An Uncleavable uPAR Mutant Allows Dissection of Signaling Pathways in uPA-dependent Cell Migration

2006 ◽  
Vol 17 (1) ◽  
pp. 367-378 ◽  
Author(s):  
Roberta Mazzieri ◽  
Silvia D'Alessio ◽  
Richard Kamgang Kenmoe ◽  
Liliana Ossowski ◽  
Francesco Blasi
Keyword(s):  
Cell Migration ◽  
Signaling Pathways ◽  
Egf Receptor ◽  
Alternative Pathway ◽  
Erk Activation ◽  
Type Plasminogen Activator ◽  
Extracellular Signal ◽  
Urokinase Type Plasminogen Activator ◽  
Dependent Cell ◽  
Epidermal Growth

Urokinase-type plasminogen activator (uPA) binding to uPAR induces migration, adhesion, and proliferation through multiple interactions with G proteins-coupled receptor FPRL1, integrins, or the epidermal growth factor (EGF) receptor (EGFR). At least two forms of uPAR are present on the cell surface: full-length and cleaved uPAR, each specifically interacting with one or more transmembrane proteins. The connection between these interactions and the effects on the signaling pathways activation is not clear. We have exploited an uPAR mutant (hcr, human cleavage resistant) to dissect the pathways involved in uPA-induced cell migration. This mutant is not cleaved by proteases, is glycosylphosphatidylinositol anchored, and binds uPA with a normal Kd. Both wild-type (wt) and hcr-uPAR are able to mediate uPA-induced migration, are constitutively associated with the EGFR, and associate with α3β1 integrin upon uPA binding. However, they engage different pathways in response to uPA. wt-uPAR requires both integrins and FPRL1 to mediate uPA-induced migration, and association of wt-uPAR to α3β1 results in uPAR cleavage and extracellular signal-regulated kinase (ERK) activation. On the contrary, hcr-uPAR does not activate ERK and does not engage FPRL1 or any other G protein-coupled receptor, but it activates an alternative pathway initiated by the formation of a triple complex (uPAR-α3β1-EGFR) and resulting in the autotyrosine phosphorylation of EGFR.

scholarly journals Differential Activation of Epidermal Growth Factor (EGF) Receptor Downstream Signaling Pathways by Betacellulin and EGF

Endocrinology ◽  
2004 ◽  
Vol 145 (9) ◽  
pp. 4232-4243 ◽  
Author(s):  
Tsugumichi Saito ◽  
Shuichi Okada ◽  
Kihachi Ohshima ◽  
Eijiro Yamada ◽  
Minoru Sato ◽  
...  
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Signaling Pathways ◽  
Tyrosine Phosphorylation ◽  
Egf Receptor ◽  
Chinese Hamster Ovary Cells ◽  
Inhibitory Effect ◽  
Erk Activation ◽  
Downstream Signaling ◽  
Epidermal Growth

Abstract To determine the downstream signaling pathways regulated by betacellulin (BTC) in comparison with epidermal growth factor (EGF), we used Chinese hamster ovary cells overexpressing the human EGF receptor (ErbB1/EGFR). The overall time-dependent activation of EGFR autophosphorylation was identical in cells treated with 1 nm BTC or 1.5 nm EGF. Analysis of site-specific EGFR phosphorylation demonstrated that the BTC and EGF tyrosine phosphorylation of Y1086 was not significantly different. In contrast, the autophosphorylation of Y1173 was markedly reduced in BTC-stimulated cells, compared with EGF stimulation that directly correlated with a reduced BTC stimulation of Shc tyrosine phosphorylation, Ras, and Raf-1 activation. On the other hand, Y1068 phosphorylation was significantly increased after BTC stimulation, compared with EGF in parallel with a greater extent of Erk phosphorylation. Expression of a dominant interfering MEK kinase 1 (MEKK1) and Y1068F EGFR more efficiently blocked the enhanced Erk activation by BTC, compared with EGF. Interestingly BTC had a greater inhibitory effect on apoptosis, compared with EGF, and expression of Y1068F EGFR abolished this enhanced inhibitory effect. Together, these data indicated that although BTC and EGF share overlapping signaling properties, the ability of BTC to enhance Erk activation occurs independent of Ras. The increased BTC activation results from a greater extent of Y1068 EGFR tyrosine phosphorylation and subsequent increased recruitment of the Grb2-MEKK1 complex to the plasma membrane, compared with EGF stimulation. The increased Erk activation by BTC associated with antiapoptotic function.

scholarly journals Differential activation of the Ras/extracellular-signal-regulated protein kinase pathway is responsible for the biological consequences induced by the Axl receptor tyrosine kinase.

1996 ◽  
Vol 16 (1) ◽  
pp. 135-145 ◽  
Author(s):  
Y W Fridell ◽  
Y Jin ◽  
L A Quilliam ◽  
A Burchert ◽  
P McCloskey ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Egf Receptor ◽  
Kinase Domain ◽  
Phosphatidylinositol 3 Kinase ◽  
Erk Activation ◽  
Interleukin 3 ◽  
Extracellular Signal ◽  
Axl Receptor Tyrosine Kinase ◽  
Epidermal Growth ◽  
Kinase Pathway

To understand the mechanism of Axl signaling, we have initiated studies to delineate downstream components in interleukin-3-dependent 32D cells by using a chimeric receptor containing the recombinant epidermal growth factor (EGF) receptor extracellular and transmembrane domains and the Axl kinase domain (EAK [for EGF receptor-Axl kinase]). We have previously shown that upon exogenous EGF stimulation, 32D-EAK cells are capable of proliferation in the absence of interleukin-3. With this system, we determined that EAK-induced cell survival and mitogenesis are dependent upon the Ras/extracellular-signal-regulated protein kinase (ERK) cascade. Although the phosphatidylinositol-3 kinase pathway is activated upon EAK signaling, it appears to be dispensable for the biological actions of the Axl kinase. Furthermore, we demonstrated that different threshold levels of Ras/ERK activation are needed to induce a block to apoptosis or proliferation in 32D cells. Recently, we have identified an Axl ligand, GAS6. Surprisingly, GAS6-stimulated 32D-Axl cells exhibited no blockage to apoptosis or mitogenic response which is correlated with the absence of Ras/ERK activation. Taken together, these data suggest that different extracellular domains dramatically alter the intracellular response of the Axl kinase. Furthermore, our data suggest that the GAS6-Axl interaction does not induce mitogenesis and that its exact role remains to be determined.

scholarly journals Wnt-dependent activation of ERK mediates repression of chondrocyte fate during calvarial development

2021 ◽  
Author(s):  
Beatriz Ibarra ◽  
Cody Machen ◽  
Radhika P. Atit
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathways ◽  
Cell Fate ◽  
Erk Signaling ◽  
Cranial Bone ◽  
Erk Activation ◽  
Cell Fate Decisions ◽  
Extracellular Signal ◽  
Dependent Cell ◽  
Calvarial Osteoblast

AbstractWnt signaling regulates cell fate decisions in diverse contexts during development, and loss of Wnt signaling in the cranial mesenchyme results in a robust and binary cell fate switch from cranial bone to ectopic cartilage. The Extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) and Wnt signaling pathways are activated during calvarial osteoblast cell fate selection. Here, we test the hypothesis that ERK signaling is a mediator of Wnt-dependent cell fate decisions in the cranial mesenchyme. First, we show that loss ofErk1/2 in the cranial mesenchyme results in a diminished domain of osteoblast marker expression and increased expression of cartilage fate markers and ectopic cartilage formation in the frontal bone primordia. Second, we show that mesenchyme Wnt/β-catenin signaling andWntlessare required for ERK activation in calvarial osteoblasts. Third, we demonstrate that Wnt and ERK signaling pathways function together to repress Sox9 expression in mouse cranial mesenchyme. Our results demonstrate a link between the Wnt and ERK signaling pathways in regulating lineage selection in a subset of calvarial cells and provide new insights into Wnt-dependent cell fate decisions.

scholarly journals Wnt-Dependent Activation of ERK Mediates Repression of Chondrocyte Fate during Calvarial Development

2021 ◽  
Vol 9 (3) ◽  
pp. 23
Author(s):  
Beatriz A Ibarra ◽  
Cody Machen ◽  
Radhika P. Atit
Keyword(s):  
Wnt Signaling ◽  
Signaling Pathways ◽  
Cell Fate ◽  
Erk Signaling ◽  
Cranial Bone ◽  
Erk Activation ◽  
Cell Fate Decisions ◽  
Extracellular Signal ◽  
Dependent Cell ◽  
Calvarial Osteoblast

Wnt signaling regulates cell fate decisions in diverse contexts during development, and loss of Wnt signaling in the cranial mesenchyme results in a robust and binary cell fate switch from cranial bone to ectopic cartilage. The Extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) and Wnt signaling pathways are activated during calvarial osteoblast cell fate selection. Here, we test the hypothesis that ERK signaling is a mediator of Wnt-dependent cell fate decisions in the cranial mesenchyme. First, we show that loss of Erk1/2 in the cranial mesenchyme results in a diminished domain of osteoblast marker expression and increased expression of cartilage fate markers and ectopic cartilage formation in the frontal bone primordia. Second, we show that mesenchyme Wnt/β-catenin signaling and Wntless are required for ERK activation in calvarial osteoblasts. Third, we demonstrate that Wnt and ERK signaling pathways function together to repress SOX9 expression in mouse cranial mesenchyme. Our results demonstrate an interaction between the Wnt and ERK signaling pathways in regulating lineage selection in a subset of calvarial cells and provide new insights into Wnt-dependent cell fate decisions.

ribbon encodes a novel BTB/POZ protein required for directed cell migration in Drosophila melanogaster

Development ◽  
2001 ◽  
Vol 128 (15) ◽  
pp. 3001-3015 ◽  
Author(s):  
Pamela L. Bradley ◽  
Deborah J. Andrew
Keyword(s):  
Cell Migration ◽  
Wnt Signaling ◽  
Signaling Pathways ◽  
Egf Receptor ◽  
Tracheal System ◽  
Directed Cell Migration ◽  
Posterior Migration ◽  
And Function ◽  
Dorsal Epidermis ◽  
Anterior Posterior

During development, directed cell migration is crucial for achieving proper shape and function of organs. One well-studied example is the embryonic development of the larval tracheal system of Drosophila, in which at least four signaling pathways coordinate cell migration to form an elaborate branched network essential for oxygen delivery throughout the larva. FGF signaling is required for guided migration of all tracheal branches, whereas the DPP, EGF receptor, and Wingless/WNT signaling pathways each mediate the formation of specific subsets of branches. Here, we characterize ribbon, which encodes a BTB/POZ-containing protein required for specific tracheal branch migration. In ribbon mutant tracheae, the dorsal trunk fails to form, and ventral branches are stunted; however, directed migrations of the dorsal and visceral branches are largely unaffected. The dorsal trunk also fails to form when FGF or Wingless/WNT signaling is lost, and we show that ribbon functions downstream of, or parallel to, these pathways to promote anterior-posterior migration. Directed cell migration of the salivary gland and dorsal epidermis are also affected in ribbon mutants, suggesting that conserved mechanisms may be employed to orient cell migrations in multiple tissues during development.

scholarly journals Estramustine Phosphate Inhibits TGF-β-Induced Mouse Macrophage Migration and Urokinase-Type Plasminogen Activator Production

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Sonja S. Mojsilovic ◽  
Slavko Mojsilovic ◽  
Suncica Bjelica ◽  
Juan F. Santibanez
Keyword(s):  
Cell Migration ◽  
Cell Motility ◽  
Plasminogen Activator ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Raw 264.7 ◽  
Estramustine Phosphate ◽  
Macrophage Cell ◽  
Type Plasminogen Activator ◽  
Urokinase Type Plasminogen Activator

Transforming growth factor-beta (TGF-β) has been demonstrated as a key regulator of immune responses including monocyte/macrophage functions. TGF-β regulates macrophage cell migration and polarization, as well as it is shown to modulate macrophage urokinase-type plasminogen activator (uPA) production, which also contributes to macrophage chemotaxis and migration toward damaged or inflamed tissues. Microtubule (MT) cytoskeleton dynamic plays a key role during the cell motility, and any interference on the MT network profoundly affects cell migration. In this study, by using estramustine phosphate (EP), which modifies MT stability, we analysed whether tubulin cytoskeleton contributes to TGF-β-induced macrophage cell migration and uPA expression. We found out that, in the murine macrophage cell line RAW 264.7, EP at noncytotoxic concentrations inhibited cell migration and uPA expression induced by TGF-β. Moreover, EP greatly reduced the capacity of TGF-β to trigger the phosphorylation and activation of its downstream Smad3 effector. Furthermore, Smad3 activation seems to be critical for the increased cell motility. Thus, our data suggest that EP, by interfering with MT dynamics, inhibits TGF-β-induced RAW 264.7 cell migration paralleled with reduction of uPA induction, in part by disabling Smad3 activation by TGF-β.

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