Interactions of Drosophila Cbl with epidermal growth factor receptors and role of Cbl in R7 photoreceptor cell development

Herman Meisner, Andrea Daga, Joanne Buxton, Belén Fernández, Anil Chawla, Utpal Banerjee, Michael P. Czech

Research output: Contribution to journalArticle

Abstract

The human proto-oncogene product c-Cbl and a similar protein in Caenorhabditis elegans (Sli-1) contain a proline-rich COOH-terminal region that binds Src homology 3 (SH3) domains of proteins such as the adapter Grb2. Cbl-Grb2 complexes can be recruited to tyrosine-phosphorylated epidermal growth factor (EGF) receptors through the SH2 domain of Grb2. Here we identify by molecular cloning a Drosophila cDNA encoding a protein (Drosophila Cbl [D-Cbl]) that shows high sequence similarity to the N- terminal region of human c-Cbl but lacks proline-rich sequences and fails to bind Grb2. Nonetheless, in COS-1 cells, expression of hemagglutinin epitope- tagged D-Cbl results in its coimmunoprecipitation with EGF receptors in response to EGF. EGF also caused tyrosine phosphorylation of D-Cbl in such cells, but no association of phosphatidylinositol 3-kinase was detected in assays using anti-p85 antibody. A point mutation in D-Cbl (G305E) that suppresses the negative regulation of LET-23 by the Cbl homolog Sli-1 in C. elegans prevented tyrosine phosphorylation of D-Cbl as well as binding to the liganded EGF receptor in COS-1 cells. Colocalization of EGF receptors with both endogenous c-Cbl or expressed D-Cbl in endosomes of EGF-treated COS-1 cells is also demonstrated by immunofluorescence microscopy. In lysates of adult transgenic Drosophila melanogaster, GST-DCbl binds to the tyrosine- phosphorylated 150-kDa torso-DER chimeric receptor. Expression of D-Cbl directed by the sevenless enhancer in intact Drosophila compromises severely the development of the R7 photoreceptor neuron. These data suggest that despite the lack of Grb2 binding sites, D-Cbl functions as a negative regulator of receptor tyrosine kinase signaling in the Drosophila eye by a mechanism that involves its association with EGF receptors or other tyrosine kinases.

Original languageEnglish
Pages (from-to)2217-2225
Number of pages9
JournalMolecular and Cellular Biology
Volume17
Issue number4
Publication statusPublished - Apr 1997

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cell Biology

Fingerprint Dive into the research topics of 'Interactions of Drosophila Cbl with epidermal growth factor receptors and role of Cbl in R7 photoreceptor cell development'. Together they form a unique fingerprint.

  • Cite this

    Meisner, H., Daga, A., Buxton, J., Fernández, B., Chawla, A., Banerjee, U., & Czech, M. P. (1997). Interactions of Drosophila Cbl with epidermal growth factor receptors and role of Cbl in R7 photoreceptor cell development. Molecular and Cellular Biology, 17(4), 2217-2225.