Gab1 and SHP-2 promote Ras/MAPK regulation of epidermal growth and differentiation

Cai, Ti; Nishida, Keigo; Hirano, Toshio; Khavari, Paul A.

doi:10.1083/jcb.200205017

Cited by 77 publications

(70 citation statements)

References 52 publications

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“…2), these results strongly support a model that Kit Tyr 567 via Gab2/Shp-2 regulates Ras activation. Furthermore, our result is also consistent with previous reports that Shp-2 via Gab1 activates Ras (49,50) in EGF signaling by preventing the recruitment of Ras-GAP to Gab1 (50). However, we could not detect any increased Ras-GAP association with the Gab2-⌬Shp-2, a Gab2 mutant that cannot bind Shp-2, compared with Gab2 WT in BMMC upon SCF stimulation.…”

Section: Discussionsupporting

confidence: 83%

The Scaffolding Adapter Gab2, via Shp-2, Regulates Kit-evoked Mast Cell Proliferation by Activating the Rac/JNK Pathway

Luo

Yang

et al. 2006

Journal of Biological Chemistry

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Section: Discussionsupporting

confidence: 83%

The Scaffolding Adapter Gab2, via Shp-2, Regulates Kit-evoked Mast Cell Proliferation by Activating the Rac/JNK Pathway

Luo

Yang

et al. 2006

Journal of Biological Chemistry

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“…High levels of ErbB-dependent autocrine ERK activation have been observed previously in NHKs, but the mechanism of activation has not been fully elucidated (Cai et al, 2002;Iordanov et al, 2002;Kansra et al, 2002;Stoll et al, 2002). We became interested in this phenomenon while trying to understand the variable levels of ERK phosphorylation we observed under basal conditions ( Figure 1A).…”

Section: Discussionmentioning

confidence: 99%

Autocrine Extracellular Signal-regulated Kinase (ERK) Activation in Normal Human Keratinocytes: Metalloproteinase-mediated Release of Amphiregulin Triggers Signaling from ErbB1 to ERK

Kansra

Stoll

Johnson

et al. 2004

MBoC

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ErbB signaling through extracellular signal-regulated kinase (ERK) has been implicated in regulating the expression of ErbB ligands in hyperproliferative skin disorders and wound healing. Here, we characterize the process of autocrine ERK activation in cultured normal human keratinocytes (NHKs) subjected to growth factor (GF) deprivation. Basal ERK phosphorylation was lower after 48 h than after 24 h of GF deprivation, and lowest at 30 -60 min after an additional medium change. ERK phosphorylation was markedly increased by low concentrations of epidermal growth factor (EGF) (0.2-1 ng/ml) that provoked only a limited increase in ErbB1 tyrosine phosphorylation and internalization. Basal ErbB tyrosine phosphorylation and ERK phosphorylation were inhibited by two different ErbB receptor tyrosine kinase inhibitors, by the ErbB1-specific neutralizing monoclonal antibody 225 IgG, by two different metalloproteinase inhibitors, and by neutralizing antibodies against amphiregulin (AR). In contrast, these responses were unaffected by neutralizing antibodies against other ErbB1 ligands or the ErbB2 inhibitors geldanamycin and AG825. The time course of autocrine ERK phosphorylation correlated with the appearance of soluble AR, and two different metalloproteinase inhibitors blocked AR release. These results define an amphiregulin-and ErbB1-dependent mechanism by which autocrine ERK activation is maintained in NHKs, even when ErbB1 autophosphorylation and internalization are limited. INTRODUCTIONThe mammalian c-ErbB family is comprised of four closely related receptor tyrosine kinases (RTKs) that interact hierarchically in response to multiple ErbB receptor ligands (Klapper et al., 2000;Olayioye et al., 2000). Ligand binding to the extracellular domain promotes receptor homo-and heterodimerization, resulting in phosphorylation of specific tyrosine residues on the cytoplasmic domain. These events lead to activation of multiple signal transduction pathways via Src homology 2 (SH2)-and phosphotyrosine binding (PTB)-domain containing cytoplasmic proteins, ultimately affecting many cellular functions, including cell migration, proliferation, and differentiation (Hubbard et al., 1998;Hackel et al., 1999). We and others have demonstrated that human skin expresses ErbB1, ErbB2, and ErbB3, but little or no ErbB4 (Press et al., 1990;Prigent et al., 1992;De Potter et al., 2001;Stoll et al., 2001).ErbB signaling plays a very important role in the reepithelialization of skin wounds, as evidenced by acceleration of burn or partial-thickness wound healing by epidermal growth factor (EGF) (Brown et al., 1989), transforming growth factor-␣ (TGF-␣) (Schultz et al., 1987), heparin-binding EGF-like growth factor (HB-EGF) (Cribbs et al., 1998), and epiregulin (Draper et al., 2003). Corneal wound healing also is markedly inhibited after treatment with ErbB receptor tyrosine kinase inhibitors (RTKIs) (Nakamura et al., 2001). Organ cultures of skin display many features of early wounds, including rapid keratinocyte cytoskeletal alterations, an early ...

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“…Thus, it would appear that EGF functions to shift the equilibrium to more active EGFR to exceed the hurdle of dephosphorylation by protein-tyrosine phosphatases and to generate signaling in a controlled manner. The Gab1 Tyr-627 and Shc Tyr-317 phosphorylation sites are of particular interest because they play important roles in EGF-mediated MAPK activation (51,52). Our finding that EGF activation yielded significantly greater fold increases in specificity constants for the Gab1 and Shc peptides, relative to EGFR autophosphorylation site peptides, suggests that ligand could be responsible for preferentially enhancing phosphorylation of Gab1 or Shc in cells, relative to other sites such as in the EGFR C terminus.…”

Section: Discussionmentioning

confidence: 99%

Ligand Regulates Epidermal Growth Factor Receptor Kinase Specificity

Fan

Wong

Deb³

et al. 2004

Journal of Biological Chemistry

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The epidermal growth factor receptor (EGFR) kinase catalyzes phosphorylation of tyrosines in its C terminus and in other cellular targets upon epidermal growth factor (EGF) stimulation. Here, by using peptides derived from EGFR autophosphorylation sites and cellular substrates, we tested the hypothesis that ligand may function to regulate EGFR kinase specificity by modulating the binding affinity of peptide sequences to the active site. Measurement of the steady-state kinetic parameters, K m and k cat , revealed that EGF did not affect the binding of EGFR peptides but increased the binding affinity for peptides corresponding to the major EGFRmediated phosphorylation sites of the adaptor proteins Gab1 (Tyr-627) and Shc (Tyr-317), and for peptides containing the previously identified optimal EGFR kinase substrate sequence EEEEYFELV (3-7-fold). Conversely, EGF stimulation increased k cat ϳ5-fold for all peptides. Thus, ligand changed the relative preference of the EGFR kinase for substrates as evidenced by EGF increases of ϳ5-fold in the specificity constants (k cat /K m ) for EGFR peptides, whereas ϳ15-40-fold increases were observed for other peptides, such as Gab1 Tyr-627. Furthermore, we demonstrate that EGF (i) increased the binding affinity of EGFR to Gab1 Tyr-627 and Shc Tyr-317 sites in purified GST fusion proteins ϳ4 -6-fold, and (ii) EGF significantly enhanced the phosphorylation of these sites, relative to EGFR autophosphorylation, in cell lysates containing the full-length Gab1 and Shc proteins. Analysis of peptides containing amino acid substitutions indicated that residues C-terminal to the target tyrosine were critical for EGF-stimulated increases in substrate binding and regulation of kinase specificity. To our knowledge, this represents the first demonstration that ligand can alter specificity of a receptor kinase toward physiologically relevant targets.Protein-tyrosine kinases, which catalyze the transfer of ␥-phosphate from ATP to tyrosine side chains of peptide and protein substrates, play a central role in cellular signaling. Receptor tyrosine kinases (RTKs) 1 constitute one class of protein kinases that consist of an extracellular ligand binding, a transmembrane, an intracellular tyrosine kinase, and a Cterminal domain that contains tyrosine phosphorylation sites (1). The epidermal growth factor receptor (EGFR, ErbB1, and HER1) is the prototypical member of the ErbB family RTKs, which also includes ErbB2 (HER2, neu), ErbB3 (HER3), and ErbB4 (HER4). Binding of growth factors that are structurally related to EGF induces a process of the receptor dimerization, kinase activation and autophosphorylation (2). EGFR activation results in recruitment and phosphorylation of cytosolic downstream targets such as Grb2-associated binding protein 1 (Gab1) (3), Src homology 2 (SH2) domain, collagen-containing protein (Shc) (4), and phospholipase C␥-1 (PLC␥-1) (5, 6). EGFR functions in the proliferation, migration, survival, and differentiation of mammalian cells (2, 7), and dysregulation of signaling by EGFR ...

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Gab1 and SHP-2 promote Ras/MAPK regulation of epidermal growth and differentiation

Cited by 77 publications

References 52 publications

The Scaffolding Adapter Gab2, via Shp-2, Regulates Kit-evoked Mast Cell Proliferation by Activating the Rac/JNK Pathway

The Scaffolding Adapter Gab2, via Shp-2, Regulates Kit-evoked Mast Cell Proliferation by Activating the Rac/JNK Pathway

Autocrine Extracellular Signal-regulated Kinase (ERK) Activation in Normal Human Keratinocytes: Metalloproteinase-mediated Release of Amphiregulin Triggers Signaling from ErbB1 to ERK

Ligand Regulates Epidermal Growth Factor Receptor Kinase Specificity

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