scholarly journals Grb2 controls phosphorylation of FGFR2 by inhibiting receptor kinase and Shp2 phosphatase activity

2013 ◽  
Vol 200 (4) ◽  
pp. 493-504 ◽  
Author(s):  
Zamal Ahmed ◽  
Chi-Chuan Lin ◽  
Kin M. Suen ◽  
Fernando A. Melo ◽  
James A Levitt ◽  
...  
Keyword(s):  
Growth Factor ◽  
Phosphatase Activity ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Sh2 Domain ◽  
Receptor Kinase ◽  
Downstream Signaling ◽  
State Growth ◽  
Kinase Phosphorylation

Constitutive receptor tyrosine kinase phosphorylation requires regulation of kinase and phosphatase activity to prevent aberrant signal transduction. A dynamic mechanism is described here in which the adaptor protein, growth factor receptor–bound protein 2 (Grb2), controls fibroblast growth factor receptor 2 (FGFR2) signaling by regulating receptor kinase and SH2 domain–containing protein tyrosine phosphatase 2 (Shp2) phosphatase activity in the absence of extracellular stimulation. FGFR2 cycles between its kinase-active, partially phosphorylated, nonsignaling state and its Shp2-dephosphorylated state. Concurrently, Shp2 cycles between its FGFR2-phosphorylated and dephosphorylated forms. Both reciprocal activities of FGFR2 and Shp2 were inhibited by binding of Grb2 to the receptor. Phosphorylation of Grb2 by FGFR2 abrogated its binding to the receptor, resulting in up-regulation of both FGFR2’s kinase and Shp2’s phosphatase activity. Dephosphorylation of Grb2 by Shp2 rescued the FGFR2–Grb2 complex. This cycling of enzymatic activity results in a homeostatic, signaling-incompetent state. Growth factor binding perturbs this background cycling, promoting increased FGFR2 phosphorylation and kinase activity, Grb2 dissociation, and downstream signaling. Grb2 therefore exerts constitutive control over the mutually dependent activities of FGFR2 and Shp2.

Indirect recruitment of the signalling adaptor Shc to the fibroblast growth factor receptor 2 (FGFR2)

2008 ◽  
Vol 416 (2) ◽  
pp. 189-199 ◽  
Author(s):  
Annika C. Schüller ◽  
Zamal Ahmed ◽  
James A. Levitt ◽  
Kin M. Suen ◽  
Klaus Suhling ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor Receptor ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Sh2 Domain ◽  
Signalling Pathways ◽  
Fibroblast Growth ◽  
Src Homology ◽  
Receptor Family ◽  
Ptb Domain

The adaptor protein Shc (Src homology and collagen-containing protein) plays an important role in the activation of signalling pathways downstream of RTKs (receptor tyrosine kinases) regulating diverse cellular functions, such as differentiation, adhesion, migration and mitogenesis. Despite being phosphorylated downstream of members of the FGFR (fibroblast growth factor receptor) family, a direct interaction of Shc with this receptor family has not been described to date. Various studies have suggested potential binding sites for the Shc PTB domain (phosphotyrosine-binding domain) and/or the SH2 (Src homology 2) domain on FGFR1, but no interaction of full-length Shc with these sites has been reported in vivo. In the present study, we investigated the importance of the SH2 domain and the PTB domain in recruitment of Shc to FGFR2(IIIc) to characterize the interaction of these two proteins. Confocal microscopy revealed extensive co-localization of Shc with FGFR2. The PTB domain was identified as the critical component of Shc which mediates membrane localization. Results from FLIM (fluorescence lifetime imaging microscopy) revealed that the interaction between Shc and FGFR2 is indirect, suggesting that the adaptor protein forms part of a signalling complex containing the receptor. We identified the non-RTK Src as a protein which potentially mediates the formation of such a ternary complex. Although an interaction between Src and Shc has been described previously, in the present study we implicate the Shc SH2 domain as a novel mediator of this association. The recruitment of Shc to FGFR2 via an indirect mechanism provides new insight into the regulation of protein assembly and activation of various signalling pathways downstream of this RTK.

scholarly journals Association of Tyrosine Phosphatase Epsilon with Microtubules Inhibits Phosphatase Activity and Is Regulated by the Epidermal Growth Factor Receptor

2007 ◽  
Vol 27 (20) ◽  
pp. 7102-7112 ◽  
Author(s):  
Tal Sines ◽  
Shira Granot-Attas ◽  
Sabrina Weisman-Welcher ◽  
Ari Elson
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Phosphatase Activity ◽  
Specific Activity ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptor ◽  
Epidermal Growth ◽  
In Cells

ABSTRACT Protein tyrosine phosphatases (PTPs) are key mediators that link physiological cues with reversible changes in protein structure and function; nevertheless, significant details concerning their regulation in vivo remain unknown. We demonstrate that PTPε associates with microtubules in vivo and is inhibited by them in a noncompetitive manner. Microtubule-associated proteins, which interact strongly with microtubules in vivo, significantly increase binding of PTPε to tubulin in vitro and further reduce phosphatase activity. Conversely, disruption of microtubule structures in cells reduces their association with PTPε, alters the subcellular localization of the phosphatase, and increases its specific activity. Activation of the epidermal growth factor receptor (EGFR) increases the PTPε-microtubule association in a manner dependent upon EGFR-induced phosphorylation of PTPε at Y638 and upon microtubule integrity. These events are transient and occur with rapid kinetics similar to EGFR autophosphorylation, suggesting that activation of the EGFR transiently down-regulates PTPε activity near the receptor by promoting the PTPε-microtubule association. Tubulin also inhibits the tyrosine phosphatase PTP1B but not receptor-type PTPμ or the unrelated alkaline phosphatase. The data suggest that reversible association with microtubules is a novel, physiologically regulated mechanism for regulation of tyrosine phosphatase activity in cells.

scholarly journals Nck-2, a Novel Src Homology2/3-containing Adaptor Protein That Interacts with the LIM-only Protein PINCH and Components of Growth Factor Receptor Kinase-signaling Pathways

1998 ◽  
Vol 9 (12) ◽  
pp. 3367-3382 ◽  
Author(s):  
Yizeng Tu ◽  
Fugang Li ◽  
Chuanyue Wu
Keyword(s):  
Growth Factor ◽  
Signaling Pathways ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Sh3 Domain ◽  
Sh2 Domain ◽  
Kinase Signaling ◽  
Egf Receptors ◽  
Growth Factor Receptor Signaling ◽  
Receptor Kinase Signaling

Many of the protein–protein interactions that are essential for eukaryotic intracellular signal transduction are mediated by protein binding modules including SH2, SH3, and LIM domains. Nck is a SH3- and SH2-containing adaptor protein implicated in coordinating various signaling pathways, including those of growth factor receptors and cell adhesion receptors. We report here the identification, cloning, and characterization of a widely expressed, Nck-related adaptor protein termed Nck-2. Nck-2 comprises primarily three N-terminal SH3 domains and one C-terminal SH2 domain. We show that Nck-2 interacts with PINCH, a LIM-only protein implicated in integrin-linked kinase signaling. The PINCH-Nck-2 interaction is mediated by the fourth LIM domain of PINCH and the third SH3 domain of Nck-2. Furthermore, we show that Nck-2 is capable of recognizing several key components of growth factor receptor kinase-signaling pathways including EGF receptors, PDGF receptor-β, and IRS-1. The association of Nck-2 with EGF receptors was regulated by EGF stimulation and involved largely the SH2 domain of Nck-2, although the SH3 domains of Nck-2 also contributed to the complex formation. The association of Nck-2 with PDGF receptor-β was dependent on PDGF activation and was mediated solely by the SH2 domain of Nck-2. Additionally, we have detected a stable association between Nck-2 and IRS-1 that was mediated primarily via the second and third SH3 domain of Nck-2. Thus, Nck-2 associates with PINCH and components of different growth factor receptor-signaling pathways via distinct mechanisms. Finally, we provide evidence indicating that a fraction of the Nck-2 and/or Nck-1 proteins are associated with the cytoskeleton. These results identify a novel Nck-related SH2- and SH3-domain–containing protein and suggest that it may function as an adaptor protein connecting the growth factor receptor-signaling pathways with the integrin-signaling pathways.

scholarly journals Off-target inhibition by active site-targeting SHP2 inhibitors

2018 ◽  
Author(s):  
Ryouhei Tsutsumi ◽  
Hao Ran ◽  
Benjamin G. Neel
Keyword(s):  
Growth Factor ◽  
Active Site ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptor ◽  
Sh2 Domain ◽  
Mitogen Activated Protein Kinase ◽  
Mitogen Activated Protein ◽  
Cellular Context ◽  
Site Targeting

AbstractDue to the involvement of SHP2 (SH2 domain-containing protein tyrosine phosphatase) in human disease, including Noonan syndrome and cancer, several inhibitors targeting SHP2 have been developed. Here, we report that the commonly used SHP2 inhibitor NSC-78788 does not exhibit robust inhibitory effects on growth factor-dependent MAPK (mitogen-activated protein kinase) pathway activation, and that the recently developed active site-targeting SHP2 inhibitors IIB-08, 11a-1, and GS-493 show off-target effects on ligand-evoked activation/trans-phosphorylation of the PDGFRβ (platelet-derived growth factor receptor β). GS-493 also inhibits purified human PDGFRβ and SRC in vitro, whereas PDGFRβ inhibition by IIB-08 and 11a-1 occurs only in the cellular context. Our results argue for extreme caution in inferring specific functions for SHP2 based on studies using these inhibitors.

scholarly journals Grb2 regulates Stat3 activation negatively in epidermal growth factor signalling

2003 ◽  
Vol 376 (2) ◽  
pp. 457-464 ◽  
Author(s):  
Tong ZHANG ◽  
Jing MA ◽  
Xinmin CAO
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Interleukin 6 ◽  
Growth Factor Receptor ◽  
Adaptor Protein ◽  
Direct Interaction ◽  
Sh2 Domain ◽  
Mitogen Activated Protein Kinase ◽  
Epidermal Growth

EGF (epidermal growth factor) binding to its receptor (EGFR) induces dimerization and autophosphorylation of the receptor at multiple tyrosine residues, which serve as docking sites for recruitment of proteins with SH2 (Src homology 2) domains that activate multiple downstream signalling pathways. The adaptor protein Grb2 (growth factor receptor-binding protein 2) binds to EGFR, which leads to activation of Ras-MAPK (mitogen-activated protein kinase) cascade. The latent transcription factors, STAT (signal transduction and activator of transcription), can also be activated by EGF in certain cell types. Since Ras-MAPK and STAT pathways are simultaneously stimulated by EGF, and Tyr-1086 and Tyr-1068 of EGFR are reported to be the binding sites for both Grb2 and Stat3, we investigated the possible regulatory role of Grb2 in STAT activation. In the present study, we report that transient expression of Grb2 specifically down-regulates EGF-stimulated tyrosine phosphorylation of Stat3, which leads to a repression of Stat3 transcriptional activity. In contrast, depletion of Grb2 by RNA interference substantially increases Stat3 tyrosine phosphorylation induced by EGF. The inhibition is neither mediated by a direct interaction between Grb2 and Stat3 nor via activation of tyrosine phosphatases. However, the repression was abolished by a mutation in the SH2 domain, but not the SH3 domains of Grb2, suggesting that inhibition involves binding of the receptor. Indeed, Grb2 inhibits the interaction between Stat3 and EGFR by competitive binding to the EGFR. On the other hand, Grb2 does not interact with the same sites as Stat3 on the interleukin-6 receptor and, therefore, has no effect on interleukin-6-induced tyrosine phosphorylation of Stat3. Taken together, our results demonstrate that, in EGF signalling, Grb2 regulates Stat3 activation negatively at the receptor level.

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