A new function for a phosphotyrosine phosphatase: linking GRB2-Sos to a receptor tyrosine kinase

1994 ◽  
Vol 14 (1) ◽  
pp. 509-517
Author(s):  
W Li ◽  
R Nishimura ◽  
A Kashishian ◽  
A G Batzer ◽  
W J Kim ◽  
...  
Keyword(s):  
Growth Factor ◽  
Intracellular Signaling ◽  
Egf Receptor ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptors ◽  
Ras Signaling ◽  
Pdgf Receptor ◽  
Phosphotyrosine Phosphatase ◽  
Src Homology

Autophosphorylated growth factor receptors provide binding sites for the src homology 2 domains of intracellular signaling molecules. In response to epidermal growth factor (EGF), the activated EGF receptor binds to a complex containing the signaling protein GRB2 and the Ras guanine nucleotide-releasing factor Sos, leading to activation of the Ras signaling pathway. We have investigated whether the platelet-derived growth factor (PDGF) receptor binds GRB2-Sos. In contrast with the EGF receptor, the GRB2 does not bind to the PDGF receptor directly. Instead, PDGF stimulation induces the formation of a complex containing GRB2; 70-, 80-, and 110-kDa tyrosine-phosphorylated proteins; and the PDGF receptor. Moreover, GRB2 binds directly to the 70-kDa protein but not to the PDGF receptor. Using a panel of PDGF beta-receptor mutants with altered tyrosine phosphorylation sites, we identified Tyr-1009 in the PDGF receptor as required for GRB2 binding. Binding is inhibited by a phosphopeptide containing a YXNX motif. The protein tyrosine phosphatase Syp/PTP1D/SHPTP2/PTP2C is approximately 70 kDa, binds to the PDGF receptor via Tyr-1009, and contains several YXNX sequences. We found that the 70-kDa protein that binds to the PDGF receptor and to GRB2 comigrates with Syp and is recognized by anti-Syp antibodies. Furthermore, both GRB2 and Sos coimmunoprecipitate with Syp from lysates of PDGF-stimulated cells, and GRB2 binds directly to tyrosine-phosphorylated Syp in vitro. These results indicate that GRB2 interacts with different growth factor receptors by different mechanisms and the cytoplasmic phosphotyrosine phosphatase Syp acts as an adapter between the PDGF receptor and the GRB2-Sos complex.

scholarly journals A new function for a phosphotyrosine phosphatase: linking GRB2-Sos to a receptor tyrosine kinase.

1994 ◽  
Vol 14 (1) ◽  
pp. 509-517 ◽  
Author(s):  
W Li ◽  
R Nishimura ◽  
A Kashishian ◽  
A G Batzer ◽  
W J Kim ◽  
...  
Keyword(s):  
Growth Factor ◽  
Intracellular Signaling ◽  
Egf Receptor ◽  
Tyrosine Phosphatase ◽  
Growth Factor Receptors ◽  
Ras Signaling ◽  
Pdgf Receptor ◽  
Phosphotyrosine Phosphatase ◽  
Src Homology

Autophosphorylated growth factor receptors provide binding sites for the src homology 2 domains of intracellular signaling molecules. In response to epidermal growth factor (EGF), the activated EGF receptor binds to a complex containing the signaling protein GRB2 and the Ras guanine nucleotide-releasing factor Sos, leading to activation of the Ras signaling pathway. We have investigated whether the platelet-derived growth factor (PDGF) receptor binds GRB2-Sos. In contrast with the EGF receptor, the GRB2 does not bind to the PDGF receptor directly. Instead, PDGF stimulation induces the formation of a complex containing GRB2; 70-, 80-, and 110-kDa tyrosine-phosphorylated proteins; and the PDGF receptor. Moreover, GRB2 binds directly to the 70-kDa protein but not to the PDGF receptor. Using a panel of PDGF beta-receptor mutants with altered tyrosine phosphorylation sites, we identified Tyr-1009 in the PDGF receptor as required for GRB2 binding. Binding is inhibited by a phosphopeptide containing a YXNX motif. The protein tyrosine phosphatase Syp/PTP1D/SHPTP2/PTP2C is approximately 70 kDa, binds to the PDGF receptor via Tyr-1009, and contains several YXNX sequences. We found that the 70-kDa protein that binds to the PDGF receptor and to GRB2 comigrates with Syp and is recognized by anti-Syp antibodies. Furthermore, both GRB2 and Sos coimmunoprecipitate with Syp from lysates of PDGF-stimulated cells, and GRB2 binds directly to tyrosine-phosphorylated Syp in vitro. These results indicate that GRB2 interacts with different growth factor receptors by different mechanisms and the cytoplasmic phosphotyrosine phosphatase Syp acts as an adapter between the PDGF receptor and the GRB2-Sos complex.

Heterodimerization of FGF-receptor 1 and PDGF-receptor-α: a novel mechanism underlying the inhibitory effect of PDGF-BB on FGF-2 in human cells

Blood ◽  
2006 ◽  
Vol 107 (5) ◽  
pp. 1896-1902 ◽  
Author(s):  
Debora Faraone ◽  
Maria S. Aguzzi ◽  
Gianluca Ragone ◽  
Katia Russo ◽  
Maurizio C. Capogrossi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Growth Factor ◽  
Intracellular Signaling ◽  
Cell Function ◽  
Umbilical Vein ◽  
Pdgf Receptor ◽  
Inhibitory Effects ◽  
Fgf Receptor ◽  
Endothelial Cell Function

Previous evidence has shown that platelet-derived growth factor-BB (PDGF-BB) and fibroblast growth factor-2 (FGF-2) directly interact with high affinity, leading to potent reciprocal inhibitory effects on bovine endothelial cells and rat vascular smooth muscle cells. In this study, we report that PDGF-BB inhibits a series of FGF-2–induced events, such as proliferation of human umbilical vein endothelial cells (HUVECs), FGF-2 cellular internalization, phosphorylation of intracellular signaling factors including p38, rac1/cdc42, MKK4, and MKK3/6, and phosphorylation of FGF-receptor 1 (FGF-R1). PDGF-receptor-α (PDGF-Rα) was found to mediate PDGF-BB inhibitory effects because its neutralization fully restored FGF-2 mitogenic activity and internalization. Additional biochemical analyses, coimmunoprecipitation experiments, and FRET analysis showed that FGF-R1 and PDGF-Rα directly interact in vitro and in vivo and that this interaction is somehow increased in the presence of the corresponding ligands FGF-2 and PDGF-BB. These results suggest that FGF-R1/PDGF-Rα heterodimerization may represent a novel endogenous mechanism to modulate the action of these receptors and their ligands and to control endothelial cell function.

RLIP76, an effector of the GTPase Ral, interacts with the AP2 complex: involvement of the Ral pathway in receptor endocytosis

2000 ◽  
Vol 113 (16) ◽  
pp. 2837-2844 ◽  
Author(s):  
V. Jullien-Flores ◽  
Y. Mahe ◽  
G. Mirey ◽  
C. Leprince ◽  
B. Meunier-Bisceuil ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Growth Factor ◽  
Egf Receptor ◽  
The Other ◽  
Ras Signaling ◽  
Receptor Endocytosis ◽  
Epidermal Growth ◽  
Two Hybrid

RLIP76 is a modular protein that was identified as a putative effector of Ral, a GTPase activated during Ras signaling. To explore further the contribution of the Ral-RLIP76 pathway to Ras signaling, we have looked for partners of RLIP76. Mu2, the medium chain of the AP2 complex is shown to interact with RLIP76. We show also that in vivo endogenous AP2 and RLIP76 form a complex and that this in vivo interaction is independent of cells being stimulated by a growth factor. Furthermore, RLIP76 differentiates AP2 from AP1 in vivo as RLIP76 differentiates mu2 from mu1 in vitro and in two hybrid assays. We show that activated Ral interferes with both tranferrin receptor endocytosis and epidermal growth factor (EGF) receptor endocytosis in HeLa cells. We propose a model where the Ral-RLIP76 pathway connects signal transduction and endocytosis through interaction on one hand between the Ras-Ral pathway and RLIP, on the other hand between RLIP and proteins belonging to the endocytotic machinery.

scholarly journals The C-terminal SH2 domain of p85 accounts for the high affinity and specificity of the binding of phosphatidylinositol 3-kinase to phosphorylated platelet-derived growth factor beta receptor.

1992 ◽  
Vol 12 (4) ◽  
pp. 1451-1459 ◽  
Author(s):  
A Klippel ◽  
J A Escobedo ◽  
W J Fantl ◽  
L T Williams
Keyword(s):  
Growth Factor ◽  
Sh2 Domain ◽  
Full Length ◽  
Platelet Derived Growth Factor ◽  
Pdgf Receptor ◽  
Sh2 Domains ◽  
High Affinity ◽  
Src Homology ◽  
Specificity Of Binding

Upon stimulation by its ligand, the platelet-derived growth factor (PDGF) receptor associates with the 85-kDa subunit of phosphatidylinositol (PI) 3-kinase. The 85-kDa protein (p85) contains two Src homology 2 (SH2) domains and one SH3 domain. To define the part of p85 that interacts with the PDGF receptor, a series of truncated p85 mutants was analyzed for association with immobilized PDGF receptor in vitro. We found that a fragment of p85 that contains a single Src homology domain, the C-terminal SH2 domain (SH2-C), was sufficient for directing the high-affinity interaction with the receptor. Half-maximal binding of SH2-C to the receptor was observed at an SH2-C concentration of 0.06 nM. SH2-C, like full-length p85, was able to distinguish between wild-type PDGF receptor and a mutant receptor lacking the PI 3-kinase binding site. An excess of SH2-C blocked binding of full-length p85 and PI 3-kinase to the receptor but did not interfere with the binding of two other SH2-containing proteins, phospholipase C-gamma and GTPase-activating protein. These results demonstrate that a region of p85 containing a single SH2 domain accounts both for the high affinity and specificity of binding of PI 3-kinase to the PDGF receptor.

scholarly journals Akt Binds to and Phosphorylates Phospholipase C-γ1 in Response to Epidermal Growth Factor

2006 ◽  
Vol 17 (5) ◽  
pp. 2267-2277 ◽  
Author(s):  
Yi Wang ◽  
Jiliang Wu ◽  
Zhixiang Wang
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Kinases ◽  
Intracellular Signaling ◽  
Egf Receptor ◽  
Sh3 Domain ◽  
Phosphatidylinositol 3 Kinase ◽  
Signaling Mechanism ◽  
Src Homology ◽  
Epidermal Growth

Both phospholipase (PL) C-γ1 and Akt (protein kinase B; PKB) are signaling proteins that play significant roles in the intracellular signaling mechanism used by receptor tyrosine kinases, including epidermal growth factor (EGF) receptor (EGFR). EGFR activates PLC-γ1 directly and activates Akt indirectly through phosphatidylinositol 3-kinase (PI3K). Many studies have shown that the PLC-γ1 pathway and PI3K–Akt pathway interact with each other. However, it is not known whether PLC-γ1 binds to Akt directly. In this communication, we identified a novel interaction between PLC-γ1 and Akt. We demonstrated that the interaction is mediated by the binding of PLC-γ1 Src homology (SH) 3 domain to Akt proline-rich motifs. We also provide a novel model to depict how the interaction between PLC-γ1 SH3 domain and Akt proline-rich motifs is dependent on EGF stimulation. In this model, phosphorylation of PLC-γ1 Y783 by EGF causes the conformational change of PLC-γ1 to allow the interaction of its SH3 domain with Akt proline-rich motifs. Furthermore, we showed that the interaction between PLC-γ1 and Akt resulted in the phosphorylation of PLC-γ1 S1248 by Akt. Finally, we showed that the interaction between PLC-γ1 and Akt enhanced EGF-stimulated cell motility.

scholarly journals Expression and catalytic activity of the tyrosine phosphatase PTP1C is severely impaired in motheaten and viable motheaten mice.

1993 ◽  
Vol 178 (6) ◽  
pp. 2157-2163 ◽  
Author(s):  
M Kozlowski ◽  
I Mlinaric-Rascan ◽  
G S Feng ◽  
R Shen ◽  
T Pawson ◽  
...  
Keyword(s):  
Tyrosine Phosphatase ◽  
Critical Role ◽  
Sh2 Domain ◽  
Loss Of Function ◽  
Phosphotyrosine Phosphatase ◽  
Gene Encoding ◽  
Phosphatase Domain ◽  
Sh2 Domains ◽  
Src Homology

Mutations in the gene encoding the phosphotyrosine phosphatase PTP1C, a cytoplasmic protein containing a COOH-terminal catalytic and two NH2-terminal Src homology 2 (SH2) domains, have been identified in motheaten (me) and viable motheaten (mev) mice and are associated with severe hemopoietic dysregulation. The me mutation is predicted to result in termination of the PTP1C polypeptide within the first SH2 domain, whereas the mev mutation creates an insertion or deletion in the phosphatase domain. No PTP1C RNA or protein could be detected in the hemopoietic tissues of me mice, nor could PTP1C phosphotyrosine phosphatase activity be isolated from cells homozygous for the me mutation. In contrast, mice homozygous for the less severe mev mutation expressed levels of full-length PTP1C protein comparable to those detected in wild type mice and the SH2 domains of mev PTP1C bound normally to phosphotyrosine-containing ligands in vitro. Nevertheless, the mev mutation induced a marked reduction in PTP1C activity. These observations provide strong evidence that the motheaten phenotypic results from loss-of-function mutations in the PTP1C gene and imply a critical role for PTP1C in the regulation of hemopoietic differentiation and immune function.

scholarly journals The epidermal growth factor receptor phosphorylates GTPase-activating protein (GAP) at Tyr-460, adjacent to the GAP SH2 domains.

1991 ◽  
Vol 11 (5) ◽  
pp. 2511-2516 ◽  
Author(s):  
X Q Liu ◽  
T Pawson
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Egf Receptor ◽  
Sh2 Domain ◽  
Ras Signaling ◽  
Gtpase Activating Protein ◽  
Epidermal Growth

GTPase-activating protein (GAP) stimulates the ability of p21ras to hydrolyze GTP to GDP. Since GAP is phosphorylated by a variety of activated or oncogenic protein-tyrosine kinases, it may couple tyrosine kinases to the Ras signaling pathway. The epidermal growth factor (EGF) receptor cytoplasmic domain phosphorylated human GAP in vitro within a single tryptic phosphopeptide. The same GAP peptide was also apparently phosphorylated on tyrosine in EGF-stimulated rat fibroblasts. Circumstantial evidence suggested that residue 460 might be the site of GAP tyrosine phosphorylation. This possibility was confirmed by phosphorylation of a synthetic peptide corresponding to the predicted tryptic peptide containing Tyr-460. Alteration of Tyr-460 to phenylalanine by site-directed mutagenesis diminished the in vitro phosphorylation of a bacterial GAP polypeptide by the EGF receptor. We conclude that Tyr-460 is a site of GAP tyrosine phosphorylation by the EGF receptor in vitro and likely in vivo. GAP Tyr-460 is located immediately C terminal to the second GAP SH2 domain, suggesting that its phosphorylation might have a role in regulating protein-protein interactions.

The epidermal growth factor receptor phosphorylates GTPase-activating protein (GAP) at Tyr-460, adjacent to the GAP SH2 domains

1991 ◽  
Vol 11 (5) ◽  
pp. 2511-2516 ◽  
Author(s):  
X Q Liu ◽  
T Pawson
Keyword(s):  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Egf Receptor ◽  
Sh2 Domain ◽  
Ras Signaling ◽  
Gtpase Activating Protein ◽  
Epidermal Growth

GTPase-activating protein (GAP) stimulates the ability of p21ras to hydrolyze GTP to GDP. Since GAP is phosphorylated by a variety of activated or oncogenic protein-tyrosine kinases, it may couple tyrosine kinases to the Ras signaling pathway. The epidermal growth factor (EGF) receptor cytoplasmic domain phosphorylated human GAP in vitro within a single tryptic phosphopeptide. The same GAP peptide was also apparently phosphorylated on tyrosine in EGF-stimulated rat fibroblasts. Circumstantial evidence suggested that residue 460 might be the site of GAP tyrosine phosphorylation. This possibility was confirmed by phosphorylation of a synthetic peptide corresponding to the predicted tryptic peptide containing Tyr-460. Alteration of Tyr-460 to phenylalanine by site-directed mutagenesis diminished the in vitro phosphorylation of a bacterial GAP polypeptide by the EGF receptor. We conclude that Tyr-460 is a site of GAP tyrosine phosphorylation by the EGF receptor in vitro and likely in vivo. GAP Tyr-460 is located immediately C terminal to the second GAP SH2 domain, suggesting that its phosphorylation might have a role in regulating protein-protein interactions.

The C-terminal SH2 domain of p85 accounts for the high affinity and specificity of the binding of phosphatidylinositol 3-kinase to phosphorylated platelet-derived growth factor beta receptor

1992 ◽  
Vol 12 (4) ◽  
pp. 1451-1459
Author(s):  
A Klippel ◽  
J A Escobedo ◽  
W J Fantl ◽  
L T Williams
Keyword(s):  
Growth Factor ◽  
Sh2 Domain ◽  
Full Length ◽  
Platelet Derived Growth Factor ◽  
Pdgf Receptor ◽  
Sh2 Domains ◽  
High Affinity ◽  
Src Homology ◽  
Specificity Of Binding

Upon stimulation by its ligand, the platelet-derived growth factor (PDGF) receptor associates with the 85-kDa subunit of phosphatidylinositol (PI) 3-kinase. The 85-kDa protein (p85) contains two Src homology 2 (SH2) domains and one SH3 domain. To define the part of p85 that interacts with the PDGF receptor, a series of truncated p85 mutants was analyzed for association with immobilized PDGF receptor in vitro. We found that a fragment of p85 that contains a single Src homology domain, the C-terminal SH2 domain (SH2-C), was sufficient for directing the high-affinity interaction with the receptor. Half-maximal binding of SH2-C to the receptor was observed at an SH2-C concentration of 0.06 nM. SH2-C, like full-length p85, was able to distinguish between wild-type PDGF receptor and a mutant receptor lacking the PI 3-kinase binding site. An excess of SH2-C blocked binding of full-length p85 and PI 3-kinase to the receptor but did not interfere with the binding of two other SH2-containing proteins, phospholipase C-gamma and GTPase-activating protein. These results demonstrate that a region of p85 containing a single SH2 domain accounts both for the high affinity and specificity of binding of PI 3-kinase to the PDGF receptor.

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