Pathways downstream of Shc and Grb2 are required for cell transformation by the tpr-Met oncoprotein.
The Tpr-Met oncoprotein, which is a member of a family of tyrosine kinase oncoproteins generated following genomic rearrangement, consists of the catalytic kinase domain of the hepatocyte growth factor/scatter factor receptor tyrosine kinase (Met) fused downstream from sequences encoded by the tpr gene. We have previously demonstrated that a single tyrosine residue in the carboxyl terminus, Tyr489, is highly phosphorylated and is essential for efficient transformation of Fr3T3 fibroblasts by Tpr-Met and for the association of Tpr-Met with the Grb2 adaptor protein and phosphatidylinositol 3'-kinase. We show here that Tyr489 is also required for association of Tpr-Met with phospholipase Cgamma and the tyrosine phosphatase, SHPTP2/Syp. To distinguish which of these substrates are required for cell transformation by the Tpr-Met oncoprotein, we generated a novel Tpr-Met mutant that selectively fails to associate with the Grb2 adaptor protein. Utilizing this mutant, together with additional Tpr-Met mutants containing Tyr to Phe substitutions, we have demonstrated that transformation of Fr3T3 fibroblasts by the Tpr-Met oncoprotein is dependent upon pathways downstream of Shc and Grb2 and that pathways downstream of phosphatidylinositol 3'-kinase, phospholipase Cgamma, and SHPTP2/Syp are insufficient for transformation.
Fixman
E D
ED
Molecular Oncology Group, Royal Victoria Hospital, Department of Medicine, McGill University, Montreal, Quebec, H3A 1A1 Canada.
Fournier
T M
TM
Kamikura
D M
DM
Naujokas
M A
MA
Park
M
M
D016475:3T3 Cells; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D017931:DNA Primers; D004789:Enzyme Activation; D051380:GRB2 Adaptor Protein; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism*; D010738:Type C Phospholipases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D017931:DNA Primers; D051380:GRB2 Adaptor Protein; C495949:Grb2 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D015514:Oncogene Proteins, Fusion; D011506:Proteins; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; D010738:Type C Phospholipases