Title

Coupling of the proto-oncogene product c-Cbl to the epidermal growth factor receptor

UMMS Affiliation

Department of Biochemistry and Molecular Biology; Program in Molecular Medicine

Publication Date

10-27-1995

Document Type

Article

Subjects

*Adaptor Proteins, Signal Transducing; Amino Acid Sequence; Cell Line; GRB2 Adaptor Protein; Humans; Immunoblotting; Molecular Sequence Data; Peptides; Phosphorylation; Precipitin Tests; Proline; Protein Binding; Proteins; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-cbl; Receptor, Epidermal Growth Factor; *Signal Transduction; Tissue Distribution; Tyrosine; *Ubiquitin-Protein Ligases

Disciplines

Life Sciences | Medicine and Health Sciences

Abstract

The proto-oncogene product, Cbl, is a 120-kDa protein present in lymphocytes that contains numerous PXXP motifs in its COOH-terminal region and constitutively binds the SH3-containing adaptor protein Grb2. Cross-linking of CD3 and CD4 receptors in Jurkat T cells causes tyrosine phosphorylation of Cbl and its association with phosphatidylinositol 3'-kinase (Meisner, H., Conway, B., Hartley, D., and Czech, M. P. (1995) Mol. Cell. Biol. 15, 3571-3578). Here we demonstrate that Cbl is also present in nonlymphoid cells, and that epidermal growth factor (EGF) elicits its rapid tyrosine phosphorylation in human embryonic 293 cells. Immunoprecipitates of Cbl from lysates of these cells contain Grb2 in the basal state, while EGF stimulation causes co-precipitation of tyrosine-phosphorylated EGF receptors. Similarly, EGF receptor immunoprecipitates from EGF-treated 293 cells contain Cbl and Grb2. Both Grb2 and EGF receptors are released from Cbl in the presence of a proline-rich peptide that binds the NH2-terminal SH3 domain of Grb2. These results indicate that autophosphorylated EGF receptors associate with the SH2 domain of Grb2, which is complexed through its SH3 domain with proline-rich regions of Cbl. Such recruitment of Cbl to EGF receptors may reflect an important mechanism for its tyrosine phosphorylation and for assembling signaling components that mediate or modulate EGF actions.

Rights and Permissions

Citation: J Biol Chem. 1995 Oct 27;270(43):25332-5.

Related Resources

Link to Article in PubMed

Journal/Book/Conference Title

The Journal of biological chemistry

PubMed ID

7592693