Increased mitogenicity of an αβ heterodimeric PDGF receptor complex correlates with lack of RasGAP binding

Ekman, Simon; Thuresson, Eva Rupp; Heldin, Carl‐Henrik; Rönnstrand, Lars

doi:10.1038/sj.onc.1202606

Cited by 63 publications

(43 citation statements)

References 39 publications

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“…6 PDGFR-aa, PDGFR-ab, and PDGFR-bb transduce a variety of cellular signals that act to prevent apoptosis (survival signaling), stimulate mitogenesis (proliferative signaling), stimulate cellular chemotaxis, and increase the concentration of intracellular calcium. [12][13][14] These effects are mediated through several well characterized downstream signaling cascades induced by the activation of PDGFRs, including the Ras/mitogen-activated protein kinase (MAPK) pathway, the phosphatidylinositol 3-kinase (PI3-K) pathway, and the phospholipase C-c1 (PLC-c1) pathway. The PI3-K pathway is critical for PDGF-induced prevention of apoptosis, actin reorganization, and cell migration.…”

Section: The Pdgf/pdgfr Axis In Cellular Signalingmentioning

confidence: 99%

Rationale for the development of IMC‐3G3, a fully human immunoglobulin G subclass 1 monoclonal antibody targeting the platelet‐derived growth factor receptor α

Shah

Loizos²,

Youssoufian³

et al. 2010

Cancer

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A large body of evidence suggests that the platelet-derived growth factor (PDGF) family and associated receptors are potential targets in oncology therapeutic development because of their critical roles in the proliferation and survival of various cancers and in the regulation and growth of the tumor stroma and blood vessels. Several small molecules that nonspecifically target the PDGF signaling axis are in current use or development as anticancer therapies. However, for the majority of these agents, PDGF and its receptors are neither the primary targets nor the principal mediators of anticancer activity. IMC-3G3, a fully human monoclonal antibody of the immunoglobulin G subclass 1, specifically binds to the human PDGF receptor a (PDGFRa) with high affinity and blocks PDGF ligand binding and PDGFRa activation. The results of preclinical studies and the frequent expression of PDGFRa in many types of cancer and in cancer-associated stroma support a rationale for the clinical development of IMC-3G3. Currently, IMC-3G3 is being evaluated in early clinical development for patients with several types of solid malignancies. Cancer 2010;116(4 suppl):1018-26.

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Section: The Pdgf/pdgfr Axis In Cellular Signalingmentioning

confidence: 99%

Rationale for the development of IMC‐3G3, a fully human immunoglobulin G subclass 1 monoclonal antibody targeting the platelet‐derived growth factor receptor α

Shah

Loizos²,

Youssoufian³

et al. 2010

Cancer

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“…The PDGF-AB isoform has been reported to possess the strongest ability to induce a mitogenic response in cells expressing both a-and b-receptors (Heidaran et al, 1991;Rupp et al, 1994). We have therefore investigated the possible unique features of the heterodimeric PDGF receptor complex compared to the homodimeric complexes, and found that in the heterodimeric complex activation of Ras and Erk2 MAP kinase were stronger and more sustained compared to homodimeric complexes (Ekman et al, 1999). We could, furthermore, show that phosphorylation of Tyr771, the RasGAP association site in the PDGF b-receptor, occurred to a much lower extent in the ab heterodimer than in bb homodimers.…”

Section: Introductionmentioning

confidence: 99%

“…Stable transfectants were obtained by selection with puromycin (Calbiochem) at a concentration of 0.5 mg/ml. PAE/a, PAE/b and PAE/bY763F/Y1009F as well as PAE/ab cells have been described earlier (Ekman et al, 1999;Mori et al, 1993;RoÈ nnstrand et al, 1999;Yokote et al, 1996). PAE cells were maintained in Ham's F-12 medium supplemented with 10% fetal calf serum (FCS).…”

Section: Plasmids Cells and Cell Culturementioning

confidence: 99%

“…Immunoprecipitation and Western blotting was performed essentially as described by (Ekman et al, 1999), with the modi®cations that cells were starved overnight in Ham's F-12 medium containing 1 mg/ml of BSA prior to the experiment. After electrotransfer and blocking, the ®lters were incubated with 5 mg/ml of pY771 antibody with or without addition of 40 mM of competing non-phosphorylated or phosphorylated peptide.…”

Section: Immunoprecipitation and Western Blottingmentioning

confidence: 99%

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SHP-2 is involved in heterodimer specific loss of phosphorylation of Tyr771 in the PDGF β-receptor

et al. 2002

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We have previously shown that the binding site for GTPase activating protein of Ras (RasGAP) in the PDGF b-receptor, Tyr771, is phosphorylated to a much lower extent in the heterodimeric con®guration of PDGF a-and b-receptors, compared to the PDGF b-receptor homodimer. The decreased recruitment of the RasGAP to the receptor leads to prolonged activation of the Ras/ MAP kinase pathway, which could explain the increase in mitogenicity seen upon induction of heterodimers. The molecular mechanism underlying these di erences was investigated. We could show that the loss of phosphorylation of Tyr771 was dependent on presence of intact binding sites for the protein tyrosine phosphatase SHP-2 on the PDGF b-receptor. Thus, in PDGF receptor mutants in which binding of SHP-2 was lost, a higher degree of phosphorylation of Tyr771 was seen, while other phosphorylation sites in the receptor remained virtually una ected. Thus, SHP-2 appears to play an important role in modulating phosphorylation of Y771, thereby controlling RasGAP recruitment and Ras/MAP kinase signaling in the heterodimeric con®guration of the PDGF receptors.

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“…In particular, through recruitment of the Ras guanine nucleotide exchange factor Sos1, Grb2 directs phosphotyrosineinduced exchange of GDP for GTP on Ras, thereby stimulating the Erk MAPK pathway (3). RasGAP and Grb2 are therefore SH2-containing proteins with opposing effects on the state of Ras activation, and data from both invertebrate and mammalian systems suggest that RTKs potentially employ Grb2 and RasGAP in combination to achieve sophisticated regulation of the Ras signaling pathway (14,15). SH2 domains generally bind short phosphotyrosine-containing peptide sequences but differ in their ability to recognize residues C-terminal to the phosphotyrosine (7,16,17).…”

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confidence: 99%

Manipulation of EphB2 Regulatory Motifs and SH2 Binding Sites Switches MAPK Signaling and Biological Activity

Tong

Elowe

Nash

et al. 2003

Journal of Biological Chemistry

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Signaling by the Eph family of receptor tyrosine kinases (RTKs) is complex, because they can interact with a variety of intracellular targets, and can potentially induce distinct responses in different cell types. In NG108 neuronal cells, activated EphB2 recruits p120RasGAP, in a fashion that is associated with downregulation of the Ras-Erk mitogen-activated kinase (MAPK) pathway and neurite retraction. To pursue the role of the Ras-MAPK pathway in EphB2-mediated growth cone collapse, and to explore the biochemical and biological functions of Eph receptors, we sought to re-engineer the signaling properties of EphB2 by manipulating its regulatory motifs and SH2 binding sites. An EphB2 mutant that retained juxtamembrane (JM) Ras-GAP binding sites but incorporated a Grb2 binding motif at an alternate RasGAP binding site within the kinase domain had little effect on basal Erk MAPK activation. In contrast, elimination of all RasGAP binding sites, accompanied by the addition of a Grb2 binding site within the kinase domain, led to an increase in phospho-Erk levels in NG108 cells following ephrin-B1 stimulation. Functional assays indicated a correlation between neurite retraction and the ability of the EphB2 mutants to down-regulate Ras-Erk MAPK signaling. These data suggest that EphB2 can be designed to repress, stabilize, or activate the Ras-Erk MAPK pathway by the manipulation of RasGAP and Grb2 SH2 domain binding sites and support the notion that Erk MAPK regulation plays a significant role in axon guidance. The behavior of EphB2 variants with mutations in the JM region and kinase domains suggests an intricate pattern of regulation and target recognition by Eph receptors.

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Increased mitogenicity of an αβ heterodimeric PDGF receptor complex correlates with lack of RasGAP binding

Cited by 63 publications

References 39 publications

Rationale for the development of IMC‐3G3, a fully human immunoglobulin G subclass 1 monoclonal antibody targeting the platelet‐derived growth factor receptor α

Rationale for the development of IMC‐3G3, a fully human immunoglobulin G subclass 1 monoclonal antibody targeting the platelet‐derived growth factor receptor α

SHP-2 is involved in heterodimer specific loss of phosphorylation of Tyr771 in the PDGF β-receptor

Manipulation of EphB2 Regulatory Motifs and SH2 Binding Sites Switches MAPK Signaling and Biological Activity

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