A Common Requirement for the Catalytic Activity and Both SH2 Domains of SHP-2 in Mitogen-activated Protein (MAP) Kinase Activation by the ErbB Family of Receptors

Abstract

The ErbB family of receptors, which include the epidermal growth factor receptor (EGFR), ErbB2, ErbB3, and ErbB4 mediate the actions of a family of bioactive polypeptides. EGF signals through EGFR, whereas heregulin (HRG) signaling is initiated through binding to either ErbB3 or ErbB4. In this report we studied the role of protein-tyrosine phosphatase SHP-2 in ErbB-mediated activation of mitogen-activated protein kinase (MAPK) by overexpressing SHP-2 mutants in COS-7 cells. We demonstrate that enzymatic activity and both NH 2 -and COOH-terminal SH2 domains of SHP-2 are required for EGF-induced MAPK activation, but not for c-Jun amino-terminal kinase stimulation or MAPK activation which occurred in response to myristoylated son of sevenless, activated Ras, or phorbol ester. Dominantnegative forms of SHP-2 had no effect on EGF-stimulated interaction of GRB2 with EGFR or SHC, nor did they influence phosphorylation of SHC and SHC/EGFR association. The same mutant SHP-2 structures that inhibited EGF-mediated stimulation of MAPK also blocked HRG ␣/␤-induced MAPK activation. EGF or HRG ␤ caused SHP-2 SH2 domains to engage multiple phosphotyrosine proteins, and mutation of either domain disrupted these associations. These results demonstrate that SHP-2 performs a common and essential function(s) in ligand-stimulated MAPK activation by the ErbB family of receptors.The ErbB family of receptors, which include epidermal growth factor receptor (EGFR 1 ; ErbB1), ErbB2, ErbB3, and ErbB4, mediate the biological actions of a family of growth factors which are structurally related to EGF (1). This family of bioactive peptides, which includes EGF, transforming growth factor ␣, amphiregulin, heparin-binding EGF-like growth factor, betacellulin, epiregulin, and heregulin ␣/␤ (HRG; neu differentiation factor, neuregulin, acetylcholine receptor-inducing activity, glial growth factor) elicits numerous cellular responses such as mitogenesis, differentiation, trophism, and motility (1). Signaling from ErbBs involves a process of receptor homo-and heterodimerization, which is initiated by engagement of ligand with a specific ErbB receptor (1). EGF and amphiregulin require the presence of EGFR for signaling (2), whereas HRG-induced signal transduction occurs after binding of ligand to either ErbB3 or ErbB4 on cells that co-express ErbB2 (3, 4).The protein-tyrosine phosphatase SHP-2 (PTP1D, SHPTP2, PTP2C, SHPTP3, or Syp) contains two Src homology 2 (SH2) domains (5) and appears to play a critical role in mitogenic responses to EGF and insulin, but not to platelet-derived growth factor (6 -10). Although it is not clear how SHP-2 functions as a positive mediator of EGF signaling, stimulation of cells with EGF has been shown to drive the association of SHP-2 with a number of proteins including a 115-kDa phosphotyrosine (Tyr(P))-containing protein (11), GRB2-associated binder-1 (Gab1) (12), SHP substrate 1 (SHPS-1)/signal-regulatory protein ␣ (SIRP␣) (13,14), and GRB2 via the COOHterminal SH3 domain of GRB2 (15). In Drosophila, membrane targeti...

The tyrosine phosphatase SHP-2 is required for mediating phosphatidylinositol 3-kinase/Akt activation by growth factors

“…As seen in Figure 2, wild-type SHP-2 expression enhanced Akt phosphorylation upon treatment with EGF (lane 4), and the R32E mutation in the N-terminal SH2 domain essentially abolished the e ect (lane 10), suggesting that the N-terminal SH2 domain is critical for SHP-2's positive role in regulating EGF-induced Akt phosphorylation. Unexpectedly, and in contrast to a dominantnegative function in regulating activation of extracellular signal-regulated kinase (ERK) (Bennett et al, 1996;Deb et al, 1998), the phosphatase inactivated mutants led to elevated but not maximal Akt phosphorylation in response to EGF stimulation (lanes 6 and 8). These data perhaps re¯ect an adaptor like activity of the SH2 domains of SHP-2 in mediating PI3K signaling initiated by EGFR activation, since SHP-2 may link EGFR and PI3K by associating with both of them in response to EGF stimulation (Vogel et al, 1993;and Figure 1).…”

“…SHP-2 has previously been suggested to be a positive regulator of MAPK activation based on the evidence that the expression of catalytically inactive mutants of SHP-2 attenuates ERK activation (Bennett et al, 1996;Deb et al, 1998). It is speculated that the SH2 domains of SHP-2, especially the N-terminal SH2 domain, also play an important role in regulating ERK activation (Deb et al, 1998;O'Reilly and Neel, 1998).…”

“…A variety of studies indicate that SHP-2 positively regulates the activation of MAPK (mitogen activated protein kinase) by growth factors and cytokines (Bennett et al, 1996;Deb et al, 1998;Shi et al, 1998;O'Reilly and Neel, 1998). However, the important physiological functions of SHP-2 may not solely result from its involvement in mediating MAP kinase pathway activation.…”

Inhibition of EGFR-mediated phosphoinositide-3-OH kinase (PI3-K) signaling and glioblastoma phenotype by Signal-Regulatory Proteins (SIRPs)

“…SIRPa1 overexpression in NIH3T3 cells inhibited DNA synthesis and MAPK phosphorylation following EGF or insulin stimulation (Kharitonenkov et al, 1997). Genetic and biochemical studies have shown that SHP2 may positively regulate MAPK signaling in response to insulin, FGF, and EGF (Noguchi et al, 1994;Tang et al, 1995;Bennett et al, 1996;Saxton et al, 1997;Deb et al, 1998;Shi et al, 1998), but attenuate MAPK activation following PDGF and neuregulin stimulation (Saxton et al, 1997;Tanowitz et al, 1999). In other studies, increased SHPS-1/SHP2 complex formation resulting from overexpression of SHPS-1 potentiated the RAS-MAPK pathway in response to insulin or integrin stimulation (Oh et al, 1999).…”

Acquired Substrate Preference for GAB1 Protein Bestows Transforming Activity to ERBB2 Kinase Lung Cancer Mutants

“…14 -16) and contains a pleckstrin homology domain, several proline-rich motifs, and conserved tyrosine residues that can be phosphorylated by activated receptor-tyrosine kinases. These GAB1 phosphotyrosines selectively bind Src homology 2 domain containing signaling proteins such as SHP2 and PI3-kinase (PI3K), and GAB1 is a critical mediator of EGFR-and ERBB2-mediated signaling (17)(18)(19)(20). EGFR-or ERBB2-mediated AKT and MAPK signaling pathways are impaired in GAB1-deficient cells, and GAB1 has been identified as a direct substrate for EGFR and other receptor kinases (21,22).…”