scholarly journals Contact-dependent inhibition of EGFR signaling by Nf2/Merlin

2007 ◽  
Vol 177 (5) ◽  
pp. 893-903 ◽  
Author(s):  
Marcello Curto ◽  
Banumathi K. Cole ◽  
Dominique Lallemand ◽  
Ching-Hui Liu ◽  
Andrea I. McClatchey
Keyword(s):  
Growth Factor Receptor ◽  
Adherens Junction ◽  
Neurofibromatosis Type ◽  
Cell Contact ◽  
Egfr Signaling ◽  
Inhibition Of Proliferation ◽  
Egfr Activation ◽  
Dependent Inhibition ◽  
Membrane Compartment ◽  
Epidermal Growth

The neurofibromatosis type 2 (NF2) tumor suppressor, Merlin, is a membrane/cytoskeleton-associated protein that mediates contact-dependent inhibition of proliferation. Here we show that upon cell–cell contact Merlin coordinates the processes of adherens junction stabilization and negative regulation of epidermal growth factor receptor (EGFR) signaling by restraining the EGFR into a membrane compartment from which it can neither signal nor be internalized. In confluent Nf2−/− cells, EGFR activation persists, driving continued proliferation that is halted by specific EGFR inhibitors. These studies define a new mechanism of tumor suppression, provide mechanistic insight into the poorly understood phenomenon of contact-dependent inhibition of proliferation, and suggest a therapeutic strategy for NF2-mutant tumors.

scholarly journals NF2/Merlin mediates contact-dependent inhibition of EGFR mobility and internalization via cortical actomyosin

2015 ◽  
Vol 211 (2) ◽  
pp. 391-405 ◽  
Author(s):  
Christine Chiasson-MacKenzie ◽  
Zachary S. Morris ◽  
Quentin Baca ◽  
Brett Morris ◽  
Joanna K. Coker ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Neurofibromatosis Type ◽  
Cell Junctions ◽  
Cell Cortex ◽  
Cell Contact ◽  
Inhibition Of Proliferation ◽  
Essential Components ◽  
Dependent Inhibition ◽  
Epidermal Growth ◽  
Actomyosin Cytoskeleton

The proliferation of normal cells is inhibited at confluence, but the molecular basis of this phenomenon, known as contact-dependent inhibition of proliferation, is unclear. We previously identified the neurofibromatosis type 2 (NF2) tumor suppressor Merlin as a critical mediator of contact-dependent inhibition of proliferation and specifically found that Merlin inhibits the internalization of, and signaling from, the epidermal growth factor receptor (EGFR) in response to cell contact. Merlin is closely related to the membrane–cytoskeleton linking proteins Ezrin, Radixin, and Moesin, and localization of Merlin to the cortical cytoskeleton is required for contact-dependent regulation of EGFR. We show that Merlin and Ezrin are essential components of a mechanism whereby mechanical forces associated with the establishment of cell–cell junctions are transduced across the cell cortex via the cortical actomyosin cytoskeleton to control the lateral mobility and activity of EGFR, providing novel insight into how cells inhibit mitogenic signaling in response to cell contact.

scholarly journals Epithelial EGF receptor signaling mediates airway hyperreactivity and remodeling in a mouse model of chronic asthma

2011 ◽  
Vol 300 (3) ◽  
pp. L414-L421 ◽  
Author(s):  
Timothy D. Le Cras ◽  
Thomas H. Acciani ◽  
Elizabeth M. Mushaben ◽  
Elizabeth L. Kramer ◽  
Patricia A. Pastura ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Epithelial Cells ◽  
Transgenic Mice ◽  
Growth Factor Receptor ◽  
Airway Hyperreactivity ◽  
Egfr Signaling ◽  
Egfr Activation ◽  
Epidermal Growth

Increases in the epidermal growth factor receptor (EGFR) have been associated with the severity of airway thickening in chronic asthmatic subjects, and EGFR signaling is induced by asthma-related cytokines and inflammation. The goal of this study was to determine the role of EGFR signaling in a chronic allergic model of asthma and specifically in epithelial cells, which are increasingly recognized as playing an important role in asthma. EGFR activation was assessed in mice treated with intranasal house dust mite (HDM) for 3 wk. EGFR signaling was inhibited in mice treated with HDM for 6 wk, by using either the drug erlotinib or a genetic approach that utilizes transgenic mice expressing a mutant dominant negative epidermal growth factor receptor in the lung epithelium (EGFR-M mice). Airway hyperreactivity (AHR) was assessed by use of a flexiVent system after increasing doses of nebulized methacholine. Airway smooth muscle (ASM) thickening was measured by morphometric analysis. Sensitization to HDM (IgG and IgE), inflammatory cells, and goblet cell changes were also assessed. Increased EGFR activation was detected in HDM-treated mice, including in bronchiolar epithelial cells. In mice exposed to HDM for 6 wk, AHR and ASM thickening were reduced after erlotinib treatment and in EGFR-M mice. Sensitization to HDM and inflammatory cell counts were similar in all groups, except neutrophil counts, which were lower in the EGFR-M mice. Goblet cell metaplasia with HDM treatment was reduced by erlotinib, but not in EGFR-M transgenic mice. This study demonstrates that EGFR signaling, especially in the airway epithelium, plays an important role in mediating AHR and remodeling in a chronic allergic asthma model.

scholarly journals Regulation of Epidermal Growth Factor Receptor Signaling by Endocytosis and Intracellular Trafficking

2001 ◽  
Vol 12 (6) ◽  
pp. 1897-1910 ◽  
Author(s):  
Patrick Burke ◽  
Kevin Schooler ◽  
H. Steven Wiley
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Growth Factor Receptor ◽  
Egfr Signaling ◽  
Egfr Activation ◽  
Early Endosomes ◽  
Epidermal Growth ◽  
Growth Factor Receptor Signaling ◽  
Regulated Trafficking

Ligand activation of the epidermal growth factor receptor (EGFR) leads to its rapid internalization and eventual delivery to lysosomes. This process is thought to be a mechanism to attenuate signaling, but signals could potentially be generated after endocytosis. To directly evaluate EGFR signaling during receptor trafficking, we developed a technique to rapidly and selectively isolate internalized EGFR and associated molecules with the use of reversibly biotinylated anti-EGFR antibodies. In addition, we developed antibodies specific to tyrosine-phosphorylated EGFR. With the use of a combination of fluorescence imaging and affinity precipitation approaches, we evaluated the state of EGFR activation and substrate association during trafficking in epithelial cells. We found that after internalization, EGFR remained active in the early endosomes. However, receptors were inactivated before degradation, apparently due to ligand removal from endosomes. Adapter molecules, such as Shc, were associated with EGFR both at the cell surface and within endosomes. Some molecules, such as Grb2, were primarily found associated with surface EGFR, whereas others, such as Eps8, were found only with intracellular receptors. During the inactivation phase, c-Cbl became EGFR associated, consistent with its postulated role in receptor attenuation. We conclude that the association of the EGFR with different proteins is compartment specific. In addition, ligand loss is the proximal cause of EGFR inactivation. Thus, regulated trafficking could potentially influence the pattern as well as the duration of signal transduction.

scholarly journals Reggies/flotillins regulate E-cadherin–mediated cell contact formation by affecting EGFR trafficking

2012 ◽  
Vol 23 (10) ◽  
pp. 1812-1825 ◽  
Author(s):  
Gonzalo P. Solis ◽  
Yvonne Schrock ◽  
Nikola Hülsbusch ◽  
Marianne Wiechers ◽  
Helmut Plattner ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Membrane Trafficking ◽  
Tyrosine Kinases ◽  
Growth Factor Receptor ◽  
Cellular Prion Protein ◽  
Cell Contact ◽  
Egfr Signaling ◽  
A431 Cells ◽  
Epidermal Growth ◽  
E Cadherin

The reggie/flotillin proteins are implicated in membrane trafficking and, together with the cellular prion protein (PrP), in the recruitment of E-cadherin to cell contact sites. Here, we demonstrate that reggies, as well as PrP down-regulation, in epithelial A431 cells cause overlapping processes and abnormal formation of adherens junctions (AJs). This defect in cell adhesion results from reggie effects on Src tyrosine kinases and epidermal growth factor receptor (EGFR): loss of reggies reduces Src activation and EGFR phosphorylation at residues targeted by Src and c-cbl and leads to increased surface exposure of EGFR by blocking its internalization. The prolonged EGFR signaling at the plasma membrane enhances cell motility and macropinocytosis, by which junction-associated E-cadherin is internalized and recycled back to AJs. Accordingly, blockage of EGFR signaling or macropinocytosis in reggie-deficient cells restores normal AJ formation. Thus, by promoting EGFR internalization, reggies restrict the EGFR signaling involved in E-cadherin macropinocytosis and recycling and regulate AJ formation and dynamics and thereby cell adhesion.

scholarly journals Enterococcus faecalis Enhances Cell Proliferation through Hydrogen Peroxide-Mediated Epidermal Growth Factor Receptor Activation

2012 ◽  
Vol 80 (10) ◽  
pp. 3545-3558 ◽  
Author(s):  
Kanitsak Boonanantanasarn ◽  
Ann Lindley Gill ◽  
YoonSing Yap ◽  
Vijayvel Jayaprakash ◽  
Maureen A. Sullivan ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Oral Cancer ◽  
Growth Factor Receptor ◽  
Egfr Signaling ◽  
Content Type ◽  
Oral Carcinogenesis ◽  
Egfr Activation ◽  
Epidermal Growth

ABSTRACTEnterococcus faecalisis a member of the intestinal and oral microbiota that may affect the etiology of colorectal and oral cancers. The mechanisms by whichE. faecalismay contribute to the initiation and progression of these cancers remain uncertain. Epidermal growth factor receptor (EGFR) signaling is postulated to play a crucial role in oral carcinogenesis. A link betweenE. faecalisand EGFR signaling in oral cancer has not been elucidated. The present study aimed to evaluate the association betweenE. faecalisand oral cancer and to determine the underlying mechanisms that linkE. faecalisto EGFR signaling. We report the high frequency ofE. faecalisinfection in oral tumors and the clinical association with EGFR activation. Using human oral cancer cells, we support the clinical findings and demonstrate thatE. faecaliscan induce EGFR activation and cell proliferation.E. faecalisactivates EGFR through production of H2O2, a signaling molecule that activates several signaling pathways. Inhibitors of H2O2(catalase) and EGFR (gefitinib) significantly blockedE. faecalis-induced EGFR activation and cell proliferation. Therefore,E. faecalisinfection of oral tumor tissues suggests a possible association betweenE. faecalisinfection and oral carcinogenesis. Interaction ofE. faecaliswith host cells and production of H2O2increase EGFR activation, thereby contributing to cell proliferation.

scholarly journals SH3KBP1 Promotes Glioblastoma Tumorigenesis by Activating EGFR Signaling

2021 ◽  
Vol 10 ◽  
Author(s):  
Hai Song ◽  
Yanpei Wang ◽  
Chaojia Shi ◽  
Jianxiang Lu ◽  
Tian Yuan ◽  
...  
Keyword(s):  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Egfr Signaling ◽  
Potential Therapeutic Target ◽  
Downstream Signaling ◽  
Protein Levels ◽  
Egfr Activation ◽  
Epidermal Growth

Glioblastoma (GBM) is the most common and aggressive brain tumor in adults. Overexpression or activation of epidermal growth factor receptor (EGFR) occurs commonly in multiple human cancers and promotes tumorigenesis. However, the underlying molecular mechanism of EGFR aberrant activation and the downstream signaling pathways remains largely unknown. In this study, we report that both SH3-domain kinase binding protein 1 (SH3KBP1) mRNA and protein levels are highly expressed in GBM and its high expression is associated with worse survival of glioma patients. In addition, we provide evidence that SH3KBP1 is prominently expressed in GBM stem cells (GSCs) and have potential to serve as a novel GSCs marker. Moreover, silencing SH3KBP1 dramatically impairs GBM cell proliferation, migration and GSCs self-renewal ability in vitro and xenograft tumors growth in vivo. Most importantly, we found that SH3KBP1 directly interacts with EGFR and may act as an adaptor protein to transduce EGFR signaling. Together, our work uncovers SH3KBP1 as a novel regulator of oncogenic EGFR signaling and also as a potential therapeutic target for GBM patients with EGFR activation.

scholarly journals Updated Insights on EGFR Signaling Pathways in Glioma

2021 ◽  
Vol 22 (2) ◽  
pp. 587
Author(s):  
Alexandru Oprita ◽  
Stefania-Carina Baloi ◽  
Georgiana-Adeline Staicu ◽  
Oana Alexandru ◽  
Daniela Elise Tache ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Treatment Strategies ◽  
Growth Factor Receptor ◽  
Standard Of Care ◽  
Egfr Signaling ◽  
Current Standard ◽  
Egfr Amplification ◽  
Epidermal Growth ◽  
New Diagnosis ◽  
Clear Clinical Benefit

Nowadays, due to recent advances in molecular biology, the pathogenesis of glioblastoma is better understood. For the newly diagnosed, the current standard of care is represented by resection followed by radiotherapy and temozolomide administration, but because median overall survival remains poor, new diagnosis and treatment strategies are needed. Due to the quick progression, even with aggressive multimodal treatment, glioblastoma remains almost incurable. It is known that epidermal growth factor receptor (EGFR) amplification is a characteristic of the classical subtype of glioma. However, targeted therapies against this type of receptor have not yet shown a clear clinical benefit. Many factors contribute to resistance, such as ineffective blood–brain barrier penetration, heterogeneity, mutations, as well as compensatory signaling pathways. A better understanding of the EGFR signaling network, and its interrelations with other pathways, are essential to clarify the mechanisms of resistance and create better therapeutic agents.

scholarly journals Dominant Enhancers of Egfr in Drosophila melanogaster: Genetic Links Between the Notch and Egfr Signaling Pathways

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1139-1153 ◽  
Author(s):  
James V Price ◽  
Edward D Savenye ◽  
David Lum ◽  
Ashton Breitkreutz
Keyword(s):  
Notch Signaling ◽  
Signaling Pathways ◽  
Growth Factor Receptor ◽  
Compound Eyes ◽  
Egfr Signaling ◽  
Wing Vein ◽  
Developmental Context ◽  
Epidermal Growth ◽  
Hypomorphic Alleles ◽  
Complex Signaling

The Drosophila epidermal growth factor receptor (EGFR) is a key component of a complex signaling pathway that participates in multiple developmental processes. We have performed and F1 screen for mutations that cause dominant enhancement of wing vein phenotypes associated with mutations in Egfr. With this screen, we have recovered mutations in Hairless (H), vein, groucho (gro), and three apparently novel loci. All of the E(Egfr)s we have identified show dominant interactions in transheterozygous combinations with each other and with alleles of N or Su(H), suggesting that they are involved in cross-talk between the N and EGFR signaling pathways. Further examination of the phenotypic interactions between Egfr, H, and gro revealed that reductions in Egfr activity enhanced both the bristle loss associated with H mutations, and the bristle hyperplasia and ocellar hypertrophy associated with gro mutations. Double mutant combinations of Egfr and gro hypomorphic alleles led to the formation of ectopic compound eyes in a dosage sensitive manner. Our findings suggest that these E(Egfr)s represent links between the Egfr and Notch signaling pathways, and that Egfr activity can either promote or suppress Notch signaling, depending on its developmental context.

scholarly journals Mdm2-Mediated Downmodulation of GRK2 Restricts Centrosome Separation for Proper Chromosome Congression

Cells ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 729
Author(s):  
Clara Reglero ◽  
Belén Ortiz del Castillo ◽  
Verónica Rivas ◽  
Federico Mayor ◽  
Petronila Penela
Keyword(s):  
Hippo Pathway ◽  
Growth Factor Receptor ◽  
Receptor Kinase ◽  
Egfr Signaling ◽  
Polyubiquitin Chains ◽  
Centrosome Separation ◽  
Chromosome Congression ◽  
Epidermal Growth ◽  
The Hippo Pathway ◽  
G Protein Coupled

The timing of centrosome separation and the distance moved apart influence the formation of the bipolar spindle, affecting chromosome stability. Epidermal growth factor receptor (EGFR) signaling induces early centrosome separation through downstream G protein-coupled receptor kinase GRK2, which phosphorylates the Hippo pathway component MST2 (Mammalian STE20-like protein kinase 2), in turn allowing NIMA kinase Nek2A activation for centrosomal linker disassembly. However, the mechanisms that counterbalance centrosome disjunction and separation remain poorly understood. We unveil that timely degradation of GRK2 by the E3 ligase Mdm2 limits centrosome separation in the G2. Both knockout expression and catalytic inhibition of Mdm2 result in GRK2 accumulation and enhanced centrosome separation before mitosis onset. Phosphorylation of GRK2 on residue S670 enables a complex pattern of non-K48-linked polyubiquitin chains assembled by Mdm2, which correlate with kinase protein degradation. Remarkably, GRK2-S670A protein fails to phosphorylate MST2 despite overcoming Mdm2-dependent degradation, which results in defective centrosome separation, shorter spindles, and abnormal chromosome congression. Conversely, extra levels of wild-type kinase in the G2 cause increased inter-centrosome distances with longer spindles, also converging in congression issues. Our findings show that the signals enabling activity of the GRK2/MST2/Nek2A axis for separation also switches on Mdm2 degradation of GRK2 to ensure accurate centrosome dynamics and proper mitotic spindle functionality.

Sign in / Sign up

Export Citation Format

Share Document