Tyrosine 1062 of Ret, which represents an intracytoplasmic docking site for multiple signaling molecules, is essential for Ret-mediated activation of phosphatidylinositol 3-Kinase (PI3-K). PI3-K, in turn, has been implicated in inducing cell survival and neoplastic transformation mediated by Ret. We have examined the mechanisms by which Ret stimulates PI3-K. Here we show that the Insulin Receptor Substrate-1 (IRS-1) is tyrosine phosphorylated and associated with the p85 regulatory subunit of PI3-K in response to Ret activation. IRS-1 coimmunoprecipitates with Ret and co-expression of IRS-1 results in the potentiation of Ret-mediated activation of Akt(PKB), a bona fide effector of PI3-K. The association with the PTB domain of IRS-1 depends on the phosphorylation of tyrosine 1062 of Ret. The deletion of asparagine 1059 (delN1059) and the substitution of leucine 1061 (L1061P), two Ret mutations identified in families affected by congenital megacolon (Hirschsprung's disease), impair the binding of IRS-1 to Ret as well as Ret-mediated Akt(PKB) stimulation. Finally, we show that Shc, which was previously identified as another ligand of Y1062 of Ret, competes with IRS-1 for the binding to Ret pY1062. All together, these findings suggest that IRS-1 is a component of the signaling pathway which leads to Ret-mediated PI3-K activation, a pathway which can be targeted by Hirschsprung-associated Ret mutations. The alternative binding of Shc and IRS-1 to Ret pY1062 can be a system to modulate the activation of different intracellular signaling pathways and to elicit different biological responses following Ret activation.

The Insulin Receptor Substrate (IRS)-1 recruits Phosphatidylinositol 3-Kinase to Ret: evidence for a competition between Shc and IRS-1 for the binding to Ret / Melillo, ROSA MARINA; Carlomagno, Francesca; DE VITA, Gabriella; Formisano, Pietro; Vecchio, Giancarlo; Fusco, Alfredo; Billaud, M.; Santoro, Massimo. - In: ONCOGENE. - ISSN 0950-9232. - STAMPA. - 20:(2001), pp. 209-218.

The Insulin Receptor Substrate (IRS)-1 recruits Phosphatidylinositol 3-Kinase to Ret: evidence for a competition between Shc and IRS-1 for the binding to Ret.

MELILLO, ROSA MARINA;CARLOMAGNO, Francesca;DE VITA, GABRIELLA;FORMISANO, PIETRO;VECCHIO, GIANCARLO;FUSCO, ALFREDO;SANTORO, MASSIMO
2001

Abstract

Tyrosine 1062 of Ret, which represents an intracytoplasmic docking site for multiple signaling molecules, is essential for Ret-mediated activation of phosphatidylinositol 3-Kinase (PI3-K). PI3-K, in turn, has been implicated in inducing cell survival and neoplastic transformation mediated by Ret. We have examined the mechanisms by which Ret stimulates PI3-K. Here we show that the Insulin Receptor Substrate-1 (IRS-1) is tyrosine phosphorylated and associated with the p85 regulatory subunit of PI3-K in response to Ret activation. IRS-1 coimmunoprecipitates with Ret and co-expression of IRS-1 results in the potentiation of Ret-mediated activation of Akt(PKB), a bona fide effector of PI3-K. The association with the PTB domain of IRS-1 depends on the phosphorylation of tyrosine 1062 of Ret. The deletion of asparagine 1059 (delN1059) and the substitution of leucine 1061 (L1061P), two Ret mutations identified in families affected by congenital megacolon (Hirschsprung's disease), impair the binding of IRS-1 to Ret as well as Ret-mediated Akt(PKB) stimulation. Finally, we show that Shc, which was previously identified as another ligand of Y1062 of Ret, competes with IRS-1 for the binding to Ret pY1062. All together, these findings suggest that IRS-1 is a component of the signaling pathway which leads to Ret-mediated PI3-K activation, a pathway which can be targeted by Hirschsprung-associated Ret mutations. The alternative binding of Shc and IRS-1 to Ret pY1062 can be a system to modulate the activation of different intracellular signaling pathways and to elicit different biological responses following Ret activation.
2001
The Insulin Receptor Substrate (IRS)-1 recruits Phosphatidylinositol 3-Kinase to Ret: evidence for a competition between Shc and IRS-1 for the binding to Ret / Melillo, ROSA MARINA; Carlomagno, Francesca; DE VITA, Gabriella; Formisano, Pietro; Vecchio, Giancarlo; Fusco, Alfredo; Billaud, M.; Santoro, Massimo. - In: ONCOGENE. - ISSN 0950-9232. - STAMPA. - 20:(2001), pp. 209-218.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/167398
Citazioni
  • ???jsp.display-item.citation.pmc??? 10
  • Scopus ND
  • ???jsp.display-item.citation.isi??? ND
social impact