Tyrosine Phosphorylation of the c-cbl Proto-oncogene Protein Product and Association with Epidermal Growth Factor (EGF) Receptor upon EGF Stimulation

doi:10.1074/jbc.270.35.20242

Tyrosine Phosphorylation of the c-cbl Proto-oncogene Protein Product and Association with Epidermal Growth Factor (EGF) Receptor upon EGF Stimulation (*)

From the (1) Department of Pharmacology, New York University Medical Center, New York, New York 10016 and the
(2) Department of Biochemistry, University of Western Australia, Nedlands, Western Australia 6009, Australia

^¶ To whom correspondence should be addressed. Tel.: 212-263-7111; Fax: 212-263-7133.

Abstract

The murine retroviral oncogene v-cbl induces pre-B cell lymphomas and myelogenous leukemias. The protein product of the mammalian c-cbl proto-oncogene is a widely expressed cytoplasmic 120-kDa protein (p120) whose normal cellular function has not been determined. Here we show that upon stimulation of human epidermal growth factor (EGF) receptor, p120 becomes strongly tyrosine-phosphorylated and associates with activated EGF receptor in vivo. A GST fusion protein containing amino acids 1-486 of p120, including a region highly conserved in nematodes, binds directly to the autophosphorylated carboxyl-terminal tail of the EGF receptor. Platelet-derived growth factor (PDGF), fibroblast growth factor (FGF), or nerve growth factor (NGF) stimulation also results in tyrosine phosphorylation of p120. Recent genetic studies in Caenorhabditis elegans indicate that Sli-1, a p120 homologue, plays a negative regulatory role in control of the Ras signaling pathway initiated by the C. elegans EGF receptor homologue. Our results indicate that p120 is involved in an early step in the EGF signaling pathway that is conserved from nematodes to mammals.

Footnotes

↵^§ On leave from the Department of Physical Chemistry, University of Granada (Spain) and was supported in part by a grant from the Direccion General de Investigacion Cientifica y Tecnica (DGICYT), Spanish Ministry of Education and Science.
↵* This work was supported by grants from Sugen Inc. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore by hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
↵¹ The abbreviations used are:

EGFR

epidermal growth factor receptor

EGF

epidermal growth factor

PDGF

platelet-derived growth factor

PDGFR

platelet-derived growth factor receptor

aFGF

acidic fibroblast growth factor

FGFR

fibroblast growth factor receptor

NGF

nerve growth factor

NGFR

nerve growth factor receptor

GST

glutathione S-transferase

PAGE

polyacrylamide gel electrophoresis

SH3

Src homology 3

DMEM

Dulbecco's modified Eagle's medium

CHO

Chinese hamster ovary.
- Received May 25, 1995.
- Revision received July 7, 1995.