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 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 The vaccinia virus-stimulated mitogen-activated protein kinase (MAPK) pathway is required for virus multiplication

2004 ◽  
Vol 381 (2) ◽  
pp. 437-446 ◽  
Author(s):  
Anderson A. ANDRADE ◽  
Patrícia N. G. SILVA ◽  
Anna C. T. C. PEREIRA ◽  
Lirlândia P. de SOUSA ◽  
Paulo C. P. FERREIRA ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Tyrosine Kinase ◽  
Vaccinia Virus ◽  
Mapk Pathway ◽  
Decisive Role ◽  
Virus Multiplication ◽  
Mitogen Activated Protein Kinase ◽  
Actin Dynamics ◽  
Kinase Activation ◽  
Mitogen Activated Protein

Early events play a decisive role in virus multiplication. We have shown previously that activation of MAPK/ERK1/2 (mitogen-activated protein kinase/extracellular-signal-regulated kinase 1/2) and protein kinase A are pivotal for vaccinia virus (VV) multiplication [de Magalhães, Andrade, Silva, Sousa, Ropert, Ferreira, Kroon, Gazzinelli and Bonjardim (2001) J. Biol. Chem. 276, 38353–38360]. In the present study, we show that VV infection provoked a sustained activation of both ERK1/2 and RSK2 (ribosomal S6 kinase 2). Our results also provide evidence that this pattern of kinase activation depends on virus multiplication and ongoing protein synthesis and is maintained independently of virus DNA synthesis. It is noteworthy that the VGF (VV growth factor), although involved, is not essential for prolonged ERK1/2 activation. Furthermore, our findings suggest that the VV-stimulated ERK1/2 activation also seems to require actin dynamics, microtubule polymerization and tyrosine kinase phosphorylation. The VV-stimulated pathway MEK/ERK1/2/RSK2 (where MEK stands for MAPK/ERK kinase) leads to phosphorylation of the ternary complex factor Elk-1 and expression of the early growth response (egr-1) gene, which kinetically paralleled the kinase activation. The recruitment of this pathway is biologically relevant, since its disruption caused a profound effect on viral thymidine kinase gene expression, viral DNA replication and VV multiplication. This pattern of sustained kinase activation after VV infection is unique. In addition, by connecting upstream signals generated at the cytoskeleton and by tyrosine kinase, the MEK/ERK1/2/RSK2 cascade seems to play a decisive role not only at early stages of the infection, i.e. post-penetration, but is also crucial to define the fate of virus progeny.

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 Activating Mutations in PTPN11 and KRAS in Canine Histiocytic Sarcomas

Genes ◽  
2019 ◽  
Vol 10 (7) ◽  
pp. 505 ◽  
Author(s):  
Marilia Takada ◽  
Lauren A. Smyth ◽  
Tuddow Thaiwong ◽  
Marlee Richter ◽  
Sarah M. Corner ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Missense Mutation ◽  
Kras Mutation ◽  
Mapk Pathway ◽  
Mitogen Activated Protein Kinase ◽  
Ptpn11 Gene ◽  
Kras Mutations ◽  
Activating Mutations ◽  
Mitogen Activated Protein ◽  
Genetic Contributions

While the genetic contributions to the predisposition of Bernese mountain dogs (BMDs) to histiocytic sarcoma (HS) remains unclear, some insights into key genetic drivers have been gained. Our group recently reported a mutation in the PTPN11 gene (E76K). We have now identified a second missense mutation in PTPN11 (G503V), and a mutation in KRAS (Q61H) present in HS cell lines. These mutations are associated with malignancies in humans, and known to be gain-of-function mutations that result in activation of the mitogen-activated protein kinase (MAPK) pathway. The goal of the present study was to evaluate the prevalence of these mutations in a large sample of HS cases from BMDs and golden retrievers, and in lymphoma cases, from a cohort of BMDs. Mutations in PTPN11 were present in HS in 41/96 (43%) BMDs, and in 3/13 (23%) golden retrievers. PTPN11 mutations E76K and G503V did not coexist in the same neoplasm. The KRAS mutation was much less frequent, with a prevalence of 3.1% (3/96). We did not identify either PTPN11 nor KRAS mutations in any of the lymphoma samples. These results point out the potential relevance of PTPN11 and KRAS mutations as activators of the oncogenic MAPK pathway for canine HS, particularly in BMDs.

scholarly journals Downregulation of the Ras–Mitogen-Activated Protein Kinase Pathway by the EphB2 Receptor Tyrosine Kinase Is Required for Ephrin-Induced Neurite Retraction

2001 ◽  
Vol 21 (21) ◽  
pp. 7429-7441 ◽  
Author(s):  
Sabine Elowe ◽  
Sacha J. Holland ◽  
Sarang Kulkarni ◽  
Tony Pawson
Keyword(s):  
Tyrosine Kinase ◽  
Receptor Tyrosine Kinase ◽  
Tyrosine Kinases ◽  
Receptor Tyrosine Kinases ◽  
Mapk Pathway ◽  
Neuronal Cells ◽  
Mitogen Activated Protein Kinase ◽  
Neurite Retraction ◽  
Mitogen Activated Protein ◽  
Stimulation Of

ABSTRACT Activation of the EphB2 receptor tyrosine kinase by clustered ephrin-B1 induces growth cone collapse and neurite retraction in differentiated NG108 neuronal cells. We have investigated the cytoplasmic signaling events associated with EphB2-induced cytoskeletal reorganization in these neuronal cells. We find that unlike other receptor tyrosine kinases, EphB2 induces a pronounced downregulation of GTP-bound Ras and consequently of the extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) pathway. A similar inhibition of the Ras-MAPK pathway was observed on stimulation of endogenous EphB2 in COS-1 cells. Inactivation of Ras, induced by ephrin B1 stimulation of NG108 neuronal cells, requires EphB2 tyrosine kinase activity and is blocked by a truncated form of p120-Ras GTPase-activating protein (p120-RasGAP), suggesting that EphB2 signals through the SH2 domain protein p120-RasGAP to inhibit the Ras-MAPK pathway. Suppression of Ras activity appears functionally important, since expression of a constitutively active variant of Ras impaired the ability of EphB2 to induce neurite retraction. In addition, EphB2 attenuated the elevation in ERK activation induced by attachment of NG108 cells to fibronectin, indicating that the EphB2 receptor can modulate integrin signaling to the Ras GTPase. These results suggest that a primary function of EphB2, a member of the most populous family of receptor tyrosine kinases, is to inactivate the Ras-MAPK pathway in a fashion that contributes to cytoskeletal reorganization and adhesion responses in neuronal growth cones.

Role of tyrosine kinase and p44/42 MAPK in D2-like receptor-mediated stimulation of Na+, K+-ATPase in kidney

2002 ◽  
Vol 282 (4) ◽  
pp. F697-F702 ◽  
Author(s):  
Vihang Narkar ◽  
Tahir Hussain ◽  
Mustafa Lokhandwala
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Mapk Pathway ◽  
Rat Kidney ◽  
Receptor Activation ◽  
Proximal Tubules ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Stimulation Of

Our laboratory has shown that dopamine D2-like receptor activation causes stimulation of Na+, K+-ATPase (NKA) activity in the proximal tubules of the rat kidney. The present study was designed to investigate the cellular signaling mechanisms mediating this response to D2-like receptor activation. We measured the stimulation of NKA activity by bromocriptine (D2-like receptor agonist) in the absence and presence of PD-98059 [p44/42 mitogen-activated protein kinase (MAPK) kinase inhibitor] and genistein (tyrosine kinase inhibitor) in renal proximal tubules. Both agents inhibited bromocriptine-mediated stimulation of NKA, suggesting the involvement of p44/42 MAPK and tyrosine kinase in this response. Additionally, we found that bromocriptine increased the phosphorylation of p44/42 MAPK in the proximal tubules, which was blocked by PD-98059 and genistein. These results show that D2-like receptor activation causes stimulation of NKA activity by means of a tyrosine kinase-p44/42 MAPK pathway in the proximal tubules of the kidney.

scholarly journals Isoform-Specific Ras Activation and Oncogene Dependence during MYC- and Wnt-Induced Mammary Tumorigenesis

2006 ◽  
Vol 26 (21) ◽  
pp. 8109-8121 ◽  
Author(s):  
Joanne W. Jang ◽  
Robert B. Boxer ◽  
Lewis A. Chodosh
Keyword(s):  
Protein Kinase ◽  
Tumor Growth ◽  
Mapk Pathway ◽  
Mammary Tumorigenesis ◽  
Mitogen Activated Protein Kinase ◽  
Activating Mutations ◽  
Ras Activation ◽  
Pathway Activation ◽  
Induced Tumors ◽  
Mitogen Activated Protein

ABSTRACT We have previously shown that c-MYC-induced mammary tumorigenesis in mice proceeds via a preferred secondary pathway involving spontaneous activating mutations in Kras2 (C. M. D'Cruz, E. J. Gunther, R. B. Boxer, J. L. Hartman, L. Sintasath, S. E. Moody, J. D. Cox, S. I. Ha, G. K. Belka, A. Golant, R. D. Cardiff, and L. A. Chodosh, Nat. Med. 7:235-239, 2001). In contrast, we now demonstrate that Wnt1-induced mammary tumorigenesis proceeds via a pathway that preferentially activates Hras1. In addition, we find that expression of oncogenic forms of Kras2 and Hras1 from their endogenous promoters has markedly different consequences for the progression of tumors to oncogene independence. Spontaneous activating Kras2 mutations occurring in either MYC- or Wnt1-induced tumors were strongly associated with oncogene-independent tumor growth following MYC or Wnt1 downregulation. In contrast, Hras1-mutant Wnt1-induced tumors consistently remained oncogene dependent. Additionally, Kras2-mutant tumors exhibited substantially higher levels of ras-GTP, phospho-Erk1/2, and phospho-Mek1/2 compared to Hras1-mutant tumors, suggesting the involvement of the ras/mitogen-activated protein kinase (MAPK) pathway in the acquisition of oncogene independence. Consistent with this, by use of carcinogen-induced ras mutations as well as knock-in mice harboring a latent activated Kras2 allele, we demonstrate that Kras2 activation strongly synergizes with both c-MYC and Wnt1 in mammary tumorigenesis and promotes the progression of tumors to oncogene independence. Together, our findings support a model for tumorigenesis in which c-MYC and Wnt1 select for the outgrowth of cells harboring mutations in specific ras isoforms and that these secondary mutations, in turn, determine the extent of ras/MAPK pathway activation and the potential for oncogene-independent growth.

scholarly journals Scaffolding Protein Gab2 Mediates Differentiation Signaling Downstream of Fms Receptor Tyrosine Kinase

2001 ◽  
Vol 21 (9) ◽  
pp. 3047-3056 ◽  
Author(s):  
Yan Liu ◽  
Brendan Jenkins ◽  
Jung Lim Shin ◽  
Larry R. Rohrschneider
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Mapk Pathway ◽  
Growth Potential ◽  
Mitogen Activated Protein Kinase ◽  
Scaffolding Protein ◽  
Macrophage Differentiation ◽  
Mapk Activity ◽  
Mitogen Activated Protein ◽  
Macrophage Colony

ABSTRACT Fms is the receptor for macrophage colony-stimulating factor (M-CSF) and contains intrinsic tyrosine kinase activity. Expression of exogenous Fms in a murine myeloid progenitor cell line, FDC-P1 (FD-Fms), results in M-CSF-dependent growth and macrophage differentiation. Previously, we described a 100-kDa protein that was tyrosine phosphorylated upon M-CSF stimulation of FD-Fms cells. In this report, we identify this 100-kDa protein as the recently cloned scaffolding protein Gab2, and we demonstrate that Gab2 associates with several molecules involved in M-CSF signaling, including Grb2, SHP2, the p85 subunit of phosphatidylinositol 3′-kinase, SHIP, and SHC. Tyrosine phosphorylation of Gab2 in response to M-CSF requires the kinase activity of Fms, but not that of Src. Overexpression of Gab2 in FD-Fms cells enhanced both mitogen-activated protein kinase (MAPK) activity and macrophage differentiation, but reduced proliferation, in response to M-CSF. In contrast, a mutant of Gab2 that is unable to bind SHP2 did not potentiate MAPK activity. Furthermore, overexpression of this mutant in FD-Fms cells inhibited macrophage differentiation and resulted in a concomitant increase in growth potential in response to M-CSF. These data indicate that Gab2 is involved in the activation of the MAPK pathway and that the interaction between Gab2 and SHP2 is essential for the differentiation signal triggered by M-CSF.

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.

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