BCR-ABL-induced oncogenesis is mediated by direct interaction with the SH2 domain of the GRB-2 adaptor protein.
BCR-ABL is a chimeric oncoprotein that exhibits deregulated tyrosine kinase activity and is implicated in the pathogenesis of Philadelphia chromosome (Ph1)-positive human leukemias. Sequences within the first exon of BCR are required to activate the transforming potential of BCR-ABL. The SH2/SH3 domain-containing GRB-2 protein links tyrosine kinases to Ras signaling. We demonstrate that BCR-ABL exists in a complex with GRB-2 in vivo. Binding of GRB-2 to BCR-ABL is mediated by the direct interaction of the GRB-2 SH2 domain with a phosphorylated tyrosine, Y177, within the BCR first exon. The BCR-ABL-GRB-2 interaction is required for activation of the Ras signaling pathway. Mutation of Y177 to phenylalanine (Y177F) abolishes GRB-2 binding and abrogates BCR-ABL-induced Ras activation. The BCR-ABL (Y177F) mutant is unable to transform primary bone marrow cultures and is impaired in its ability to transform Rat1 fibroblasts. These findings implicate activation of Ras function as an important component in BCR-ABL-mediated transformation and demonstrate that GRB-2 not only functions in normal development and mitogenesis but also plays a role in oncogenesis.
Pendergast
A M
AM
Department of Pharmacology, Duke University Medical Center, Durham, North Carolina 27710.
Quilliam
L A
LA
Cripe
L D
LD
Bassing
C H
CH
Dai
Z
Z
Li
N
N
Batzer
A
A
Rabun
K M
KM
Der
C J
CJ
Schlessinger
J
J
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002460:Cell Line; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D005091:Exons; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism*; D051380:GRB2 Adaptor Protein; D016313:Genes, abl; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive; D009036:Moths; D016297:Mutagenesis, Site-Directed; D010649:Phenylalanine; D017354:Point Mutation; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011506:Proteins / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics; D051562:Proto-Oncogene Proteins c-bcr; D011519:Proto-Oncogenes; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000378:metabolism; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; D011506:Proteins; D011518:Proto-Oncogene Proteins; D011993:Recombinant Fusion Proteins; D010649:Phenylalanine; D011505:Protein-Tyrosine Kinases; D016044:Fusion Proteins, bcr-abl; C496613:BCR protein, human; D051562:Proto-Oncogene Proteins c-bcr