Ephrin-B1 transduces signals to activate integrin-mediated migration,attachment and angiogenesis

2002 ◽  
Vol 115 (15) ◽  
pp. 3073-3081 ◽  
Author(s):  
Uyen Huynh-Do ◽  
Cécile Vindis ◽  
Hua Liu ◽  
Douglas Pat Cerretti ◽  
Jeffrey T. McGrew ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Tyrosine Kinases ◽  
Cell Attachment ◽  
Transmembrane Proteins ◽  
Terminal Protein ◽  
Ephb Receptor ◽  
Bidirectional Signaling ◽  
Terminal Amino ◽  
And Migration

Ephrin-B/EphB family proteins are implicated in bidirectional signaling and were initially defined through the function of their ectodomain sequences in activating EphB receptor tyrosine kinases. Ephrin-B1-3 are transmembrane proteins sharing highly conserved C-terminal cytoplasmic sequences. Here we use a soluble EphB1 ectodomain fusion protein (EphB1/Fc) to demonstrate that ephrin-B1 transduces signals that regulate cell attachment and migration. EphB1/Fc induced endothelial ephrin-B1 tyrosine phosphorylation, migration and integrin-mediated (αvβ3 andα 5β1) attachment and promoted neovascularization, in vivo, in a mouse corneal micropocket assay. Activation of ephrin-B1 by EphB1/Fc induced phosphorylation of p46 JNK but not ERK-1/2 or p38 MAPkinases. By contrast, mutant ephrin-B1s bearing either a cytoplasmic deletion (ephrin-B1ΔCy) or a deletion of four C-terminal amino acids(ephrin-B1ΔPDZbd) fail to activate p46 JNK. Transient expression of intact ephin-B1 conferred EphB1/Fc migration responses on CHO cells, whereas the ephrin-B1ΔCy and ephrin-B1ΔPDZbd mutants were inactive. Thus ephrin-B1 transduces `outside-in' signals through C-terminal protein interactions that affect integrin-mediated attachment and migration.

scholarly journals Glycocalyx-mediated Cell Adhesion and Migration

2020 ◽  
Author(s):  
Samuel Schmidt ◽  
Bettina Weigelin ◽  
Joost te Riet ◽  
Veronika te Boekhorst ◽  
Mariska te Lindert ◽  
...  
Keyword(s):  
Cell Attachment ◽  
Adaptive Process ◽  
Nanoscale Interactions ◽  
Cell Adhesion And Migration ◽  
3D Environments ◽  
And Migration ◽  
Force Range ◽  
Membrane Deformations

SummaryCell migration is a force-dependent adaptive process mediated by integrin-dependent adhesion as well as other yet poorly defined interactions to the extracellular matrix. Using enzymatic multi-targeted digestion of sugar moieties on the surface of mesenchymal cells and leukocytes after interference with integrin function, we demonstrate that the surface glycocalyx represents an independent adhesion system. The glycocalyx mediates cell attachment to ECM ligand in the 100-500 pN force range and amoeboid migration in 3D environments in vitro and in vivo. Glycan-based adhesions consist of actin-rich membrane deformations and appositions associated with bleb-like and other protrusions forming complex-shaped sub-micron contact sites to ECM fibrils. These data implicate the glycocalyx in mediating generic stickiness to support nanoscale interactions (nanogrips) between the cell surface and ECM, mechano-coupling, and migration.

scholarly journals Regulation of vasculogenesis and angiogenesis by EphB/ephrin-B2 signaling between endothelial cells and surrounding mesenchymal cells

Blood ◽  
2002 ◽  
Vol 100 (4) ◽  
pp. 1326-1333 ◽  
Author(s):  
Yuichi Oike ◽  
Yasuhiro Ito ◽  
Koichi Hamada ◽  
Xiu-Qin Zhang ◽  
Keishi Miyata ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Tyrosine Kinases ◽  
Molecular Mechanisms ◽  
Neuronal Development ◽  
Receptor Tyrosine Kinases ◽  
Vascular Endothelial Cells ◽  
Mesenchymal Cells ◽  
Ephb Receptor ◽  
Vasculogenesis And Angiogenesis

Although the cellular and molecular mechanisms governing angiogenesis are only beginning to be understood, signaling through endothelial-restricted receptors, particularly receptor tyrosine kinases, has been shown to play a pivotal role in these events. Recent reports show that EphB receptor tyrosine kinases and their transmembrane-type ephrin-B2 ligands play essential roles in the embryonic vasculature. These studies suggest that cell-to-cell repellent effects due to bidirectional EphB/ephrin-B2 signaling may be crucial for vascular development, similar to the mechanism described for neuronal development. To test this hypothesis, we disrupted the precise expression pattern of EphB/ephrin-B2 in vivo by generating transgenic (CAGp-ephrin-B2 Tg) mice that express ephrin-B2 under the control of a ubiquitous and constitutive promoter, CMV enhancer-β-actin promoter-β-globin splicing acceptor (CAG). These mice displayed an abnormal segmental arrangement of intersomitic vessels, while such anomalies were not observed in Tie-2p-ephrin-B2 Tg mice in which ephrin-B2 was overexpressed in only vascular endothelial cells (ECs). This finding suggests that non-ECs expressing ephrin-B2 alter the migration of ECs expressing EphB receptors into the intersomitic region where ephrin-B2 expression is normally absent. CAGp-ephrin-B2 Tg mice show sudden death at neonatal stages from aortic dissecting aneurysms due to defective recruitment of vascular smooth muscle cells to the ascending aorta. EphB/ephrin-B2 signaling between endothelial cells and surrounding mesenchymal cells plays an essential role in vasculogenesis, angiogenesis, and vessel maturation.

scholarly journals Dual Effects ofβ3Integrin Subunit Expression on Human Pancreatic Cancer Models

2010 ◽  
Vol 33 (5-6) ◽  
pp. 191-205 ◽  
Author(s):  
S. Marchán ◽  
S. Pérez-Torras ◽  
A. Vidal ◽  
J. Adan ◽  
F. Mitjans ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Rho Gtpases ◽  
Cell Attachment ◽  
Human Pancreatic Cancer ◽  
Cell Growth And Migration ◽  
Subunit Expression ◽  
And Migration

Background: Pancreatic cancer, the fifth leading cause of adult cancer death in Western countries, lacks early detection, and displays significant dissemination ability. Accumulating evidence shows that integrin-mediated cell attachment to the extracellular matrix induces phenotypes and signaling pathways that regulate tumor cell growth and migration.Methods: In view of these findings, we examined the role ofβ3in pancreatic cancer by generating two stableβ3-expressing pancreatic human cell lines and characterizing their behavior in vitro and in vivo.Results: Transduction ofβ3selectively augmented the functional membraneαvβ3integrin levels, as evident from the enhanced adhesion and migration abilities related to active Rho GTPases. No effects on in vitro anchorage-dependent growth, but higher anoikis were detected inβ3-overexpressing cells. Moreover, tumors expressingβ3displayed reduced growth. Interestingly, treatment of mice with anαv-blocking antibody inhibited the growth ofβ3-expressing tumors to a higher extent.Conclusion: Our results collectively support the hypothesis thatαvβ3integrin has dual actions depending on the cell environment, and provide additional evidence on the role of integrins in pancreatic cancer, which should eventually aid in improving prediction of the effects of therapies addressed to modulate integrin activities in these tumors.

Ga13 and Talin Coordinate integrin Inside-out and Outside-In Signaling by “time-sharing” of b3 cytoplasmic Domain

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 162-162
Author(s):  
Haixia Gong ◽  
Xiaoping Du
Keyword(s):  
Conflicts Of Interest ◽  
Cytoplasmic Domain ◽  
Time Sharing ◽  
Protein Subunit ◽  
Fibrinogen Binding ◽  
Bidirectional Signaling ◽  
And Migration ◽  
Inside Out

Abstract Abstract 162 The bidirectional signaling of integrins mediates cell adhesion, spreading, retraction and migration. The binding of talin and kindlins to the cytoplasmic domain of integrin b3 subunit transmits inside-out signals to induce integrin activation. Ligand-induced outside-in signaling requires the binding of a G protein subunit, Ga13, and a tyrosine kinase, c-Src, to the b3 cytoplasmic domain. It is unclear how the short cytoplasmic domain of b3 accommodates these molecules and allows coordinated bidirectional signaling. Here we show that Ga13 and talin are mutually exclusive in binding to b3 both in vivo and in vitro. Increasing expression level of talin head or full-length talin in CHO123 cell decreases Ga13-b3 association. Ga13 also competes with talin head for GST-b3 binding in purified binding system. More importantly, talin is associated with b3 only in inside-out signaling during platelet aggregation. Following integrin ligation, however, Ga13 binds to b3, replacing talin. The Ga13 binding site located between K729-T741 within the talin binding region. However, Ga13 binding and signaling require a distinct ExE733 motif (EEE in b3) conserved in most integrin b subunits that is not required for talin binding but flanked by talin binding sequences on both sides. Interference of Ga13 binding to integrin b3 cytoplasmic domain by myristorylated b3 peptide (Myr-EEERA735) or by point-mutating the EEE motif to AAA selectively inhibits outside-in signaling, thus inhibited cell spreading on fibrinogen, accelerated RhoA activation and inhibited c-Src activity. But they have no effect on talin-dependent inside-out signaling judged by fibrinogen binding assay. In conclusion, our data suggest that the timed share of binding sites in b3 between Ga13 and talin coordinates bidirectional integrin signaling. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The low-complexity domains of the KMT2D protein regulate histone monomethylation transcription to facilitate pancreatic cancer progression

2021 ◽  
Vol 26 (1) ◽  
Author(s):  
Weihan Li ◽  
Lei Wu ◽  
Hui Jia ◽  
Zenghua Lin ◽  
Renhao Zhong ◽  
...  
Keyword(s):  
Cancer Progression ◽  
Protein Interactions ◽  
Treatment Strategies ◽  
Low Complexity ◽  
Enzyme Complex ◽  
Wild Type ◽  
Histone Lysine Methyltransferase ◽  
Core Proteins ◽  
And Migration

Abstract Background Liquid–liquid phase separation (LLPS) within the nucleus is directly linked to driving gene expression through transcriptional complexes. Histone lysine methyltransferase 2D (KMT2D) is widely present in many cancers. It is known to epigenetically stimulate the expression of genes associated with tumorigenesis and metastasis. Our analyses show that KMT2D possesses two distinct low-complexity domains (LCDs) capable of driving the assembly of membrane-less condensates. The dependence of the mechanisms underlying monomethylation of H3K4 on the LLPS microenvironment derived from KMT2D LCDs is unclear in tumor. Methods KMT2D LCD-depletion cells were used to investigate tumor cell proliferation, apoptosis, and migration. We identified some core proteins, including WDR5, RBBP5, and ASH2L, which are involved in the KMT2D-associated catalytic complex in KMT2D LCD-deficient cells to further elucidate the mechanism that decreases monomethylation of H3K4. We also evaluated the viability of KMT2D LCD-deficient cells in vivo. Finally, using 1,6-hexanediol (HD), an inhibitor of LLPS, we determined cell activities associated with KMT2D function in wild-type PANC-1 cells. Results Without the LLPS microenvironment in KMT2D LCD-deficient cells or wild-type PANC-1 cells treated with HD, the WDR5 protein was significantly less stable and the protein–protein interactions between the components of the KMT2D–enzyme complex were attenuated, impairing the formation of the complex. Moreover, with the decrease in H3K4me1 level at enhancers, transcription factors such as LIFR and KLF4 were markedly downregulated, effectively inhibiting tumor progression. In xenograft tumor models, PANC-1 cells lacking the KMT2D LCDs showed effectively suppressed tumor growth compared to normal cells. Conclusions Our data indicate that the two low-complexity domains of the KMT2D protein could form a stable LLPS microenvironment, promoting the KMT2D catalysis of H3K4 monomethylation through stabilization of the WDR5 protein and KMT2D–enzyme complex. Therefore, finding ways to regulate the LLPS microenvironment will be benefitial for new cancer treatment strategies.

scholarly journals Expression of Eph receptors and their ligands, ephrins, during lipopolysaccharide fever in rats

2005 ◽  
Vol 21 (2) ◽  
pp. 152-160 ◽  
Author(s):  
Andrei I. Ivanov ◽  
Alexandre A. Steiner ◽  
Adrienne C. Scheck ◽  
Andrej A. Romanovsky
Keyword(s):  
Tyrosine Kinases ◽  
Eph Receptors ◽  
Phase 2 ◽  
Eph Receptor ◽  
Cellular Events ◽  
Cell Adhesion And Migration ◽  
Transcriptional Changes ◽  
And Migration

Erythropoietin-producing hepatocellular (Eph) receptor tyrosine kinases and their ligands, ephrins, are involved in embryogenesis and oncogenesis by mediating cell adhesion and migration. Although ephrins can be induced by bacterial LPS in vitro, whether they are involved in inflammation in vivo is unknown. Using differential mRNA display, we found that a febrigenic dose of LPS (50 μg/kg iv) induces a strong transcriptional upregulation of ephrin-A1 in rat liver. We confirmed this finding by real-time RT-PCR. We then quantified the mRNA expression of different ephrins and Eph receptors at phases 1–3 of LPS fever in different organs. Febrile phases 2 (90 min post-LPS) and 3 (300 min) were characterized by robust upregulation (up to 16-fold) and downregulation (up to 21-fold) of several ephrins and Eph receptors. With the exception of EphA2, which showed upregulation in the brain at phase 2, expressional changes of Eph receptors and ephrins were limited to the LPS-processing organs: liver and lung. Characteristic, counter-directed changes in expressional regulation of Eph receptors and their corresponding ligands were found: upregulation of EphA2, downregulation of ephrin-A1 in the liver and lung at phase 2; downregulation of EphB3, upregulation of ephrin-B2 in the liver at phase 2; downregulation of EphA1 and EphA3, upregulation of ephrins-A1 and -A3 in liver at phase 3. In the liver, transcriptional changes of EphA2 and EphB3 at phase 2 were confirmed at protein level. These coordinated, phase-specific responses suggest that different sets of ephrins and Eph receptors may be involved in cellular events (such as disruption of tissue barriers and leukocyte transmigration) underlying different stages of systemic inflammatory response to LPS.

scholarly journals Eph/Ephrin-Based Protein Complexes: The Importance of cis Interactions in Guiding Cellular Processes

2022 ◽  
Vol 8 ◽  
Author(s):  
Alessandra Cecchini ◽  
D. D. W. Cornelison
Keyword(s):  
Tyrosine Kinases ◽  
Cellular Response ◽  
Protein Complexes ◽  
Cell Types ◽  
Linear Process ◽  
Diverse Range ◽  
Ephb Receptor ◽  
Cellular Context ◽  
Associated Proteins ◽  
And Migration

Although intracellular signal transduction is generally represented as a linear process that transmits stimuli from the exterior of a cell to the interior via a transmembrane receptor, interactions with additional membrane-associated proteins are often critical to its success. These molecules play a pivotal role in mediating signaling via the formation of complexes in cis (within the same membrane) with primary effectors, particularly in the context of tumorigenesis. Such secondary effectors may act to promote successful signaling by mediating receptor-ligand binding, recruitment of molecular partners for the formation of multiprotein complexes, or differential signaling outcomes. One signaling family whose contact-mediated activity is frequently modulated by lateral interactions at the cell surface is Eph/ephrin (EphA and EphB receptor tyrosine kinases and their ligands ephrin-As and ephrin-Bs). Through heterotypic interactions in cis, these molecules can promote a diverse range of cellular activities, including some that are mutually exclusive (cell proliferation and cell differentiation, or adhesion and migration). Due to their broad expression in most tissues and their promiscuous binding within and across classes, the cellular response to Eph:ephrin interaction is highly variable between cell types and is dependent on the cellular context in which binding occurs. In this review, we will discuss interactions between molecules in cis at the cell membrane, with emphasis on their role in modulating Eph/ephrin signaling.

scholarly journals Multiple SH2-mediated interactions in v-src-transformed cells.

1992 ◽  
Vol 12 (3) ◽  
pp. 1366-1374 ◽  
Author(s):  
C A Koch ◽  
M F Moran ◽  
D Anderson ◽  
X Q Liu ◽  
G Mbamalu ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Tyrosine Kinases ◽  
Protein Tyrosine Kinase ◽  
Kinase Domain ◽  
Sh2 Domain ◽  
Protein Tyrosine ◽  
Sh2 Domains ◽  
Phosphorylated Proteins

The Src homology 2 (SH2) domain is a noncatalytic region which is conserved among a number of signaling and transforming proteins, including cytoplasmic protein-tyrosine kinases and Ras GTPase-activating protein (GAP). Genetic and biochemical data indicate that the SH2 domain of the p60v-src (v-Src) protein-tyrosine kinase is required for full v-src transforming activity and may direct the association of v-Src with specific tyrosine-phosphorylated proteins. To test the ability of the v-Src SH2 domain to mediate protein-protein interactions, v-Src polypeptides were expressed as fusion proteins in Escherichia coli. The bacterial v-Src SH2 domain bound a series of tyrosine-phosphorylated proteins in a lysate of v-src-transformed Rat-2 cells, including prominent species of 130 and 62 kDa (p130 and p62). The p130 and p62 tyrosine-phosphorylated proteins that complexed v-Src SH2 in vitro also associated with v-Src in v-src-transformed Rat-2 cells; this in vivo binding was dependent on the v-Src SH2 domain. In addition to binding soluble p62 and p130, the SH2 domains of v-Src, GAP, and v-Crk directly recognized these phosphotyrosine-containing proteins which had been previously denatured and immobilized on a filter. In addition, the SH2 domains of GAP and v-Crk bound to the GAP-associated protein p190 immobilized on a nitrocellulose membrane. These results show that SH2 domains bind directly to tyrosine-phosphorylated proteins and that the Src SH2 domain can bind phosphorylated targets of the v-Src kinase domain.(ABSTRACT TRUNCATED AT 250 WORDS)

Involvement of the Lyn Interactome in the Regulation of Erythropoiesis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 463-463
Author(s):  
Evan Ingley ◽  
David J. McCarthy ◽  
Amy L. Samuels ◽  
Jessica R. Schneider ◽  
Christine J. Payne ◽  
...  
Keyword(s):  
Cell Biology ◽  
Cell Attachment ◽  
Ex Vivo ◽  
Cell Signalling ◽  
Adaptor Protein ◽  
Normal Function ◽  
Negative Regulator ◽  
Signalling Molecules ◽  
And Migration

Abstract Src family kinases, such as Lyn, are involved in signalling pathways regulating a myriad of cellular processes. We have shown previously that Lyn is involved in differentiation signals emanating from activated erythropoietin (Epo) receptors. We have highlighted the importance of Lyn to red cell maturation in vivo with Lyn−/ − mice, which develop anaemia and display extramedullary stress erythropoiesis. Here, we show that ex vivo cultures of primary Lyn−/ − erythroblasts display an imbalance between proliferation and differentiation. In addition we have identified several new Lyn pathways. One centres on Cbp (Csk binding protein), an adaptor protein that recruits negative regulators Csk/Ctk. Our data show that Lyn phosphorylates Cbp, which then recruits Csk/Ctk to suppress Lyn kinase activity. Intriguingly, through the use of a phosphotyrosine-specific yeast two-hybrid assay that we developed, phosphorylated Cbp also binds SOCS1, another well-characterised negative regulator of cell signalling - this results in elevated ubiquitination and degradation of Lyn in Epo-stimulated erythroid cells. Altering Cbp expression in primary erythroblasts significantly affected their ability to transmit Epo-receptor signals and differentiate correctly. Another Lyn pathway we have identified centres on a novel molecule we termed LACM, which transmits Lyn signals to Vav2 and Nckβ via phospho-tyrosine-specific interactions. These novel associations regulate the cytoskeleton/cell shape, which lead to changes in cell attachment and migration. Significantly, primary erythroblasts from Lyn−/ − mice display altered subcellular localization of LACM. Another novel Lyn interactor (LIAR) regulates nuclear import/export of signalling molecules - impairing LIAR’s normal function inhibits primary erythroblast development. Taken together, these results illustrate that Lyn is intimately involved in multiple signalling complexes, which play crucial roles in regulating numerous aspects of red blood cell biology.

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