scholarly journals Grb2 binding induces phosphorylation-independent activation of Shp2

2019 ◽  
Author(s):  
Chi-Chuan Lin ◽  
Lukasz Wieteska ◽  
Kin Man Suen ◽  
Arnout Kalverda ◽  
Zamal Ahmed ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Tyrosine Phosphatase ◽  
Adaptor Protein ◽  
Cancer Cell Line ◽  
Mitogen Activated Protein Kinase ◽  
Activating Mutations ◽  
Mapk Signalling ◽  
Mitogen Activated Protein ◽  
Cancer Types

AbstractThe regulation of phosphatase activity is fundamental to the control of intracellular signalling and in particular the tyrosine kinase-mediated mitogen-activated protein kinase (MAPK) pathway. Shp2 is a ubiquitously expressed protein tyrosine phosphatase and its kinase-induced hyperactivity is associated with many cancer types. In non-stimulated cells we find that binding of the adaptor protein, Grb2, in its monomeric state initiates Shp2 activity independent of phosphatase phosphorylation. Grb2 forms a bidentate interaction with both the N-terminal SH2 and the catalytic domains of Shp2, releasing the phosphatase from its auto-inhibited conformation. Grb2 typically exists as a dimer in the cytoplasm. However, its monomeric state prevails under basal conditions when it is expressed at low concentration, or when it is constitutively phosphorylated on a specific tyrosine residue (Y160). Thus, Grb2 can activate Shp2 and downstream signal transduction, in the absence of extracellular growth factor stimulation or kinase-activating mutations, in response to defined cellular conditions. We identify a polypeptide biotool capable of blocking the Grb2-Shp2 interaction. This peptide down-regulates Shp2 activity in vitro and MAPK signalling in a cancer cell line.

scholarly journals Grb2 binding induces phosphorylation-independent activation of Shp2

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Chi-Chuan Lin ◽  
Lukasz Wieteska ◽  
Kin Man Suen ◽  
Arnout P. Kalverda ◽  
Zamal Ahmed ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Mapk Pathway ◽  
Tyrosine Phosphatase ◽  
Adaptor Protein ◽  
Mitogen Activated Protein Kinase ◽  
Activating Mutations ◽  
Catalytic Domains ◽  
Mitogen Activated Protein ◽  
Direct Binding ◽  
Cancer Types

AbstractThe regulation of phosphatase activity is fundamental to the control of intracellular signalling and in particular the tyrosine kinase-mediated mitogen-activated protein kinase (MAPK) pathway. Shp2 is a ubiquitously expressed protein tyrosine phosphatase and its kinase-induced hyperactivity is associated with many cancer types. In non-stimulated cells we find that binding of the adaptor protein Grb2, in its monomeric state, initiates Shp2 activity independent of phosphatase phosphorylation. Grb2 forms a bidentate interaction with both the N-terminal SH2 and the catalytic domains of Shp2, releasing the phosphatase from its auto-inhibited conformation. Grb2 typically exists as a dimer in the cytoplasm. However, its monomeric state prevails under basal conditions when it is expressed at low concentration, or when it is constitutively phosphorylated on a specific tyrosine residue (Y160). Thus, Grb2 can activate Shp2 and downstream signal transduction, in the absence of extracellular growth factor stimulation or kinase-activating mutations, in response to defined cellular conditions. Therefore, direct binding of Grb2 activates Shp2 phosphatase in the absence of receptor tyrosine kinase up-regulation.

scholarly journals Role of Ptc2 Type 2C Ser/Thr Phosphatase in Yeast High-Osmolarity Glycerol Pathway Inactivation

2002 ◽  
Vol 1 (6) ◽  
pp. 1032-1040 ◽  
Author(s):  
Christian Young ◽  
James Mapes ◽  
Jennifer Hanneman ◽  
Sheikha Al-Zarban ◽  
Irene Ota
Keyword(s):  
Catalytic Domain ◽  
Mapk Pathway ◽  
Tyrosine Phosphatase ◽  
Mitogen Activated Protein Kinase ◽  
Growth Defect ◽  
Negative Regulators ◽  
High Osmolarity ◽  
High Osmolarity Glycerol ◽  
Mitogen Activated Protein

ABSTRACT Three type 2C Ser/Thr phosphatases (PTCs) are negative regulators of the yeast Saccharomyces cerevisiae high-osmolarity glycerol mitogen-activated protein kinase (MAPK) pathway. Ptc2 and Ptc3 are 75% identical to each other and differ from Ptc1 in having a noncatalytic domain. Previously, we showed that Ptc1 inactivates the pathway by dephosphorylating the Hog1 MAPK; Ptc1 maintains low basal Hog1 activity and dephosphorylates Hog1 during adaptation. Here, we examined the function of Ptc2 and Ptc3. First, deletion of PTC2 and/or PTC3 together with PTP2, encoding the protein tyrosine phosphatase that inactivates Hog1, produced a strong growth defect at 37°C that was dependent on HOG1, providing further evidence that PTC2 and PTC3 are negative regulators. Second, overexpression of PTC2 inhibited Hog1 activation but did not affect Hog1-Tyr phosphorylation, suggesting that Ptc2 inactivates the pathway by dephosphorylating the Hog1 activation loop phosphothreonine (pThr) residue. Indeed, in vitro studies confirmed that Ptc2 was specific for Hog1-pThr. Third, deletion of both PTC2 and PTC3 led to greater Hog1 activation upon osmotic stress than was observed in wild-type strains, although no obvious change in Hog1 inactivation during adaptation was seen. These results indicate that Ptc2 and Ptc3 differ from Ptc1 in that they limit maximal Hog1 activity. The function of the Ptc2 noncatalytic domain was also examined. Deletion of this domain decreased V max by 1.6-fold and increased Km by 2-fold. Thus Ptc2 requires an additional amino acid sequence beyond the catalytic domain defined for PTCs for full activity.

scholarly journals APPL1 mediates adiponectin-stimulated p38 MAPK activation by scaffolding the TAK1-MKK3-p38 MAPK pathway

2011 ◽  
Vol 300 (1) ◽  
pp. E103-E110 ◽  
Author(s):  
Xiaoban Xin ◽  
Lijun Zhou ◽  
Caleb M. Reyes ◽  
Feng Liu ◽  
Lily Q. Dong
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Mapk Pathway ◽  
Adaptor Protein ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Mapk Activation ◽  
P38 Mapk Pathway ◽  
Mitogen Activated Protein

The adaptor protein APPL1 mediates the stimulatory effect of adiponectin on p38 mitogen-activated protein kinase (MAPK) signaling, yet the underlying mechanism remains unclear. Here we show that, in C2C12 cells, overexpression or suppression of APPL1 enhanced or suppressed, respectively, adiponectin-stimulated p38 MAPK upstream kinase cascade, consisting of transforming growth factor-β-activated kinase 1 (TAK1) and mitogen-activated protein kinase kinase 3 (MKK3). In vitro affinity binding and coimmunoprecipitation experiments revealed that TAK1 and MKK3 bind to different regions of APPL1, suggesting that APPL1 functions as a scaffolding protein to facilitate adiponectin-stimulated p38 MAPK activation. Interestingly, suppressing APPL1 had no effect on TNFα-stimulated p38 MAPK phosphorylation in C2C12 myotubes, indicating that the stimulatory effect of APPL1 on p38 MAPK activation is selective. Taken together, our study demonstrated that the TAK1-MKK3 cascade mediates adiponectin signaling and uncovers a scaffolding role of APPL1 in regulating the TAK1-MKK3-p38 MAPK pathway, specifically in response to adiponectin stimulation.

scholarly journals Regulation of EphB2 activation and cell repulsion by feedback control of the MAPK pathway

2008 ◽  
Vol 183 (5) ◽  
pp. 933-947 ◽  
Author(s):  
Alexei Poliakov ◽  
Maria L. Cotrina ◽  
Andrea Pasini ◽  
David G. Wilkinson
Keyword(s):  
Feedback Loop ◽  
Fibroblast Growth Factor Receptor ◽  
Mapk Pathway ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptor ◽  
Mitogen Activated Protein Kinase ◽  
Eph Receptor ◽  
Mitogen Activated Protein ◽  
Mediate Cell ◽  
Cell Repulsion

In this study, we investigated whether the ability of Eph receptor signaling to mediate cell repulsion is antagonized by fibroblast growth factor receptor (FGFR) activation that can promote cell invasion. We find that activation of FGFR1 in EphB2-expressing cells prevents segregation, repulsion, and collapse responses to ephrinB1 ligand. FGFR1 activation leads to increased phosphorylation of unstimulated EphB2, which we show is caused by down-regulation of the leukocyte common antigen–related tyrosine phosphatase receptor that dephosphorylates EphB2. In addition, FGFR1 signaling inhibits further phosphorylation of EphB2 upon stimulation with ephrinB1, and we show that this involves a requirement for the mitogen-activated protein kinase (MAPK) pathway. In the absence of activated FGFR1, EphB2 activates the MAPK pathway, which in turn promotes EphB2 activation in a positive feedback loop. However, after FGFR1 activation, the induction of Sprouty genes inhibits the MAPK pathway downstream of EphB2 and decreases cell repulsion and segregation. These findings reveal a novel feedback loop that promotes EphB2 activation and cell repulsion that is blocked by transcriptional targets of FGFR1.

scholarly journals Inhibition of Epithelial CC-Family Chemokine Synthesis by the Synthetic Chalcone DMPF-1 via Disruption of NF-κB Nuclear Translocation and Suppression of Experimental Asthma in Mice

2015 ◽  
Vol 2015 ◽  
pp. 1-15 ◽  
Author(s):  
Revathee Rajajendram ◽  
Chau Ling Tham ◽  
Mohamad Nadeem Akhtar ◽  
Mohd Roslan Sulaiman ◽  
Daud Ahmad Israf
Keyword(s):  
Airway Hyperresponsiveness ◽  
Nuclear Translocation ◽  
Mapk Pathway ◽  
Pulmonary Inflammation ◽  
Mitogen Activated Protein Kinase ◽  
Epithelial Cell Line ◽  
Cell Hyperplasia ◽  
Mitogen Activated Protein ◽  
Cc Chemokines

Asthma is associated with increased pulmonary inflammation and airway hyperresponsiveness. The interaction between airway epithelium and inflammatory mediators plays a key role in the pathogenesis of asthma.In vitrostudies evaluated the inhibitory effects of 3-(2,5-dimethoxyphenyl)-1-(5-methylfuran-2-yl)prop-2-en-1-one (DMPF-1), a synthetic chalcone analogue, upon inflammation in the A549 lung epithelial cell line. DMPF-1 selectively inhibited TNF-α-stimulated CC chemokine secretion (RANTES, eotaxin-1, and MCP-1) without any effect upon CXC chemokine (GRO-αand IL-8) secretion. Western blot analysis further demonstrated that the inhibitory activity resulted from disruption of p65NF-κB nuclear translocation without any effects on the mitogen-activated protein kinase (MAPK) pathway. Treatment of ovalbumin-sensitized and ovalbumin-challenged BALB/c mice with DMPF-1 (0.2–100 mg/kg) demonstrated significant reduction in the secretion and gene expression of CC chemokines (RANTES, eotaxin-1, and MCP-1) and Th2 cytokines (IL-4, IL-5, and IL-13). Furthermore, DMPF-1 treatment inhibited eosinophilia, goblet cell hyperplasia, peripheral blood total IgE, and airway hyperresponsiveness in ovalbumin-sensitized and ovalbumin-challenged mice. In conclusion, these findings demonstrate the potential of DMPF-1, a nonsteroidal compound, as an antiasthmatic agent for further pharmacological evaluation.

scholarly journals Phosphorylation of High-Mobility Group Protein A2 by Nek2 Kinase during the First Meiotic Division in Mouse Spermatocytes

2004 ◽  
Vol 15 (3) ◽  
pp. 1224-1232 ◽  
Author(s):  
Silvia Di Agostino ◽  
Monica Fedele ◽  
Paolo Chieffi ◽  
Alfredo Fusco ◽  
Pellegrino Rossi ◽  
...  
Keyword(s):  
Mapk Pathway ◽  
Chromatin Condensation ◽  
High Mobility ◽  
Mitogen Activated Protein Kinase ◽  
Dependent Manner ◽  
Correct Process ◽  
High Mobility Group Protein ◽  
Mitogen Activated Protein ◽  
Pachytene Spermatocytes

The mitogen-activated protein kinase (MAPK) pathway is required for maintaining the chromatin condensed during the two meiotic divisions and to avoid a second round of DNA duplication. However, molecular targets of the MAPK pathway on chromatin have not yet been identified. Here, we show that the architectural chromatin protein HMGA2 is highly expressed in male meiotic cells. Furthermore, Nek2, a serine-threonine kinase activated by the MAPK pathway in mouse pachytene spermatocytes, directly interacts with HMGA2 in vitro and in mouse spermatocytes. The interaction does not depend on the activity of Nek2 and seems constitutive. On progression from pachytene to metaphase, Nek2 is activated and HMGA2 is phosphorylated in an MAPK-dependent manner. We also show that Nek2 phosphorylates in vitro HMGA2 and that this phosphorylation decreases the affinity of HMGA2 for DNA and might favor its release from the chromatin. Indeed, we find that most HMGA2 associates with chromatin in mouse pachytene spermatocytes, whereas it is excluded from the chromatin upon the G2/M progression. Because hmga2-/- mice are sterile and show a dramatic impairment of spermatogenesis, it is possible that the functional interaction between HMGA2 and Nek2 plays a crucial role in the correct process of chromatin condensation in meiosis.

Phosphorylation of Argonaute 2 at serine-387 facilitates its localization to processing bodies

2008 ◽  
Vol 413 (3) ◽  
pp. 429-436 ◽  
Author(s):  
Yan Zeng ◽  
Heidi Sankala ◽  
Xiaoxiao Zhang ◽  
Paul R. Graves
Keyword(s):  
Protein Kinase ◽  
P38 Mapk ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Phosphorylation Site ◽  
Mitogen Activated Protein Kinase ◽  
Processing Bodies ◽  
Mitogen Activated Protein

Ago (Argonaute) proteins are essential effectors of RNA-mediated gene silencing. To explore potential regulatory mechanisms for Ago proteins, we examined the phosphorylation of human Ago2. We identified serine-387 as the major Ago2 phosphorylation site in vivo. Phosphorylation of Ago2 at serine-387 was significantly induced by treatment with sodium arsenite or anisomycin, and arsenite-induced phosphorylation was inhibited by a p38 MAPK (mitogen-activated protein kinase) inhibitor, but not by inhibitors of JNK (c-Jun N-terminal kinase) or MEK [MAPK/ERK (extracellular-signal-regulated kinase) kinase]. MAPKAPK2 (MAPK-activated protein kinase-2) phosphorylated bacterially expressed full-length human Ago2 at serine-387 in vitro, but not the S387A mutant. Finally, mutation of serine-387 to an alanine residue or treatment of cells with a p38 MAPK inhibitor reduced the localization of Ago2 to processing bodies. These results suggest a potential regulatory mechanism for RNA silencing acting through Ago2 serine-387 phosphorylation mediated by the p38 MAPK pathway.

scholarly journals Positive and negative selection invoke distinct signaling pathways.

1996 ◽  
Vol 184 (1) ◽  
pp. 9-18 ◽  
Author(s):  
J Alberola-Ila ◽  
K A Hogquist ◽  
K A Swan ◽  
M J Bevan ◽  
R M Perlmutter
Keyword(s):  
T Cell ◽  
Positive Selection ◽  
Negative Selection ◽  
Mapk Pathway ◽  
Cell Receptor ◽  
Dominant Negative ◽  
Mapk Cascade ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein

During T cell development, interaction of the T cell receptor (TCR) with cognate ligands in the thymus may result in either maturation (positive selection) or death (negative selection). The intracellular pathways that control these opposed outcomes are not well characterized. We have generated mice expressing dominant-negative Ras (dnRas) and Mek-1 (dMek) transgenes simultaneously, either in otherwise normal animals, or in animals expressing a transgenic TCR, thereby permitting a comprehensive analysis of peptide-specific selection. In this system, thymocyte maturation beyond the CD4+8+ stage is blocked almost completely, whereas negative selection, assessed using an in vitro deletion protocol, is quantitatively intact. This suggests that activation of the mitogen-activated protein kinase (MAPK) cascade is necessary for positive selection, but irrelevant for negative selection. Generation of gamma/delta and of CD4-8- alpha/beta T cells proceeds normally despite blockade of the MAPK cascade. Hence, only cells that mature via conventional, TCR-mediated repertoire selection require activation of the MAPK pathway to complete their maturation.

scholarly journals Identification of RAS-Mitogen-Activated Protein Kinase Signaling Pathway Modulators in an ERF1 Redistribution® Screen

2006 ◽  
Vol 11 (4) ◽  
pp. 423-434 ◽  
Author(s):  
Charlotta Grånäs ◽  
Betina Kerstin Lundholt ◽  
Frosty Loechel ◽  
Hans-Christian Pedersen ◽  
Sara Petersen Bjørn ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Signaling Pathway ◽  
Kinase Inhibitors ◽  
Mapk Pathway ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
A Cell ◽  
Protein Kinase Signaling

The RAS-mitogen-activated protein kinase (MAPK) signaling pathway has a central role in regulating the proliferation and survival of both normal and tumor cells. This pathway has been 1 focus area for the development of anticancer drugs, resulting in several compounds, primarily kinase inhibitors, in clinical testing. The authors have undertaken a cell-based, high-throughput screen using a novel ERF1 Redistribution® assay to identify compounds that modulate the signaling pathway. The hit compounds were subsequently tested for activity in a functional cell proliferation assay designed to selectively detect compounds inhibiting the proliferation of MAPK pathway-dependent cancer cells. The authors report the identification of 2 cell membrane-permeable compounds that exhibit activity in the ERF1 Redistribution® assay and selectively inhibit proliferation of MAPK pathway-dependent malignant melanoma cells at similar potencies (IC50 =< 5 μM). These compounds have drug-like structures and are negative in RAF, MEK, and ERK in vitro kinase assays. Drugs belonging to these compound classes may prove useful for treating cancers caused by excessive MAPK pathway signaling. The results also show that cell-based, high-content Redistribution® screens can detect compounds with different modes of action and reveal novel targets in a pathway known to be disease relevant.

scholarly journals MEK-inhibitor-mediated rescue of skeletal myopathy caused by activating Hras mutation in a Costello syndrome mouse model

2021 ◽  
Author(s):  
William E. Tidyman ◽  
Alice F. Goodwin ◽  
Yoshiko Maeda ◽  
Ophir D. Klein ◽  
Katherine A. Rauen
Keyword(s):  
Mouse Model ◽  
Mapk Pathway ◽  
Mek Inhibitor ◽  
Mapk Signaling ◽  
Mitogen Activated Protein Kinase ◽  
Costello Syndrome ◽  
Skeletal Myopathy ◽  
Mitogen Activated Protein

Costello syndrome (CS) is a congenital disorder caused by heterozygous activating germline HRAS mutations in the canonical Ras/mitogen-activated protein kinase (Ras/MAPK) pathway. CS is one of the RASopathies, a large group of syndromes due to mutations within various components of the Ras/MAPK pathway. An important part of the phenotype that greatly impacts quality of life is hypotonia. To gain a better understanding of the mechanisms underlying hypotonia in CS, a mouse model with an activating HrasG12V allele was utilized. We identified a skeletal myopathy that was due in part to an inhibition of embryonic myogenesis and myofiber formation, resulting in a reduction of myofiber size and number that led to reduced muscle mass and strength. In addition to hyperactivation of the Ras/MAPK and PI3K/AKT pathways, there was a significant reduction of p38 signaling, as well as global transcriptional alterations consistent with the myopathic phenotype. Inhibition of Ras/MAPK pathway signaling using a MEK inhibitor rescued the HrasG12V myopathy phenotype both in vitro and in vivo, demonstrating that increased MAPK signaling is the main cause of the muscle phenotype in CS.

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