The SH2-containing adapter protein GRB10 interacts with BCR-ABL

Oncogene. 1998 Aug 27;17(8):941-8. doi: 10.1038/sj.onc.1202024.


Bcr-Abl is an oncogenic tyrosine kinase expressed in tumor cells of CML and a subset of ALL which in its unregulated and activated state is thought to cause cell transformation and leukemia. Bcr-Abl contains several autophosphorylation sites which serve as potential docking sites for SH2-containing signaling molecules. Mutational analysis has indicated that these autophosphorylation sites play a critical role in the transforming capability of Bcr-Abl. It has been shown that the SH2-containing adapter protein Grb2 binds to the autophosphorylation site Tyr(p)177 whereby it couples Bcr-Abl to the Ras pathway. The biological consequences of this interaction, however, are presently unclear. A Tyr177-mutated Bcr-Abl which lacks the ability to interact with the Grb2-SH2 domain still transforms myeloid cells and generates tumors in nude mice. We performed a yeast two-hybrid screen to identify signaling proteins which bind to distinct Bcr-Abl autophosphorylation sites. Autophosphorylation of Bcr-Abl in yeast was accomplished by using the DNA binding protein LexA which permits dimerization and crossphosphorylation of the fused bait. Using a LexA-Bcr-Abl full length fusion protein as bait, we identified several SH2-containing proteins. Among them we confirmed molecules already shown by others to interact with Bcr-Abl, in vivo, including Grb2, PI-3-kinase and Crk indicating that dimerization in yeast leads to autophosphorylation of tyrosine residues crucial for Bcr-Abl signaling in vivo. More importantly, we identified the SH2-containing protein Grb10 as a new binding partner for Bcr-Abl. This binding occurs in a phosphotyrosine-dependent manner at Bcr sites of Bcr-Abl. Both Abl and Bcr alone, as well as a kinase-defective Bcr-Abl, failed to interact with Grb10 in yeast. Mutational analysis uncovered a new SH2 binding site in Bcr-Abl located between Bcr aa242-446, which is different from the Grb2 binding site. Binding could be demonstrated in vitro and also in vivo as shown by co-immunoprecipitation analysis in CML cells. Using a temperature sensitive Bcr-Abl stably overexpressed in hematopoetic cells, we demonstrated that complex formation of Grb10 with Bcr-Abl was kinase activation-dependent in vivo. Notably, a Bcr-Abl mutant protein (Bcr/1-242-Abl) which lacks the ability to interact with Grb10 partially alleviated IL-3 dependence of Ba/F3 cells, indicating that the Grb10/Bcr-Abl interaction is important for Bcr-Abl-induced IL-3 independence of Ba/F3 cells. In addition, the Bcr/1-242-Abl mutant has a reduced capacity to induce focus formation in fibroblasts.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorption
  • Cell Line
  • Cell Transformation, Neoplastic / genetics
  • Enzyme Activation
  • ErbB Receptors / metabolism
  • Fusion Proteins, bcr-abl / genetics
  • Fusion Proteins, bcr-abl / metabolism*
  • GRB10 Adaptor Protein
  • Genetic Vectors / metabolism
  • Humans
  • Leukemia, Myelogenous, Chronic, BCR-ABL Positive / metabolism
  • Mutation
  • Protein Binding
  • Protein-Tyrosine Kinases / metabolism
  • Proteins / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Transfection
  • Tumor Cells, Cultured
  • src Homology Domains*


  • Proteins
  • GRB10 Adaptor Protein
  • ErbB Receptors
  • Protein-Tyrosine Kinases
  • Fusion Proteins, bcr-abl