Loss of the exon encoding the juxtamembrane domain is essential for the oncogenic activation of TPR-MET.
TPR-MET, a transforming counterpart of the c-MET proto-oncogene detected in experimental and human cancer, results from fusion of the MET kinase domain with a dimerization motif encoded by TPR. In this rearrangement the exons encoding the Met extracellular, transmembrane and juxtamembrane domains are lost. The juxtamembrane domain has been suggested to be a regulatory region endowed with negative feedback control. To understand whether its absence is critical for the generation of the Tpr-Met transforming potential, we produced a chimeric molecule (Tpr-juxtaMet) with a conserved juxtamembrane domain. The presence of the domain (aa 962-1009) strongly inhibited Tpr-Met dependent cell transformation. Cell proliferation, anchorage-independent growth, motility and invasion were also impaired. The enzymatic behavior of Tpr-Met and Tpr-juxtaMet was the same, while Tpr-juxtaMet ability to associate cytoplasmic signal transducers and to elicit downstream signaling was severely impaired. These data indicate that the presence of the juxtamembrane domain counterbalances the Tpr-Met transforming potential and therefore the loss of the exon encoding the juxtamembrane domain is crucial in the generation of the active TPR-MET oncogene.
Vigna
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E
Institute for Cancer Research and Treatment (IRCC), University of Torino School of Medicine, Italy.
Gramaglia
D
D
Longati
P
P
Bardelli
A
A
Comoglio
P M
PM
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002461:Cell Line, Transformed; D002471:Cell Transformation, Neoplastic / Q000235:genetics*; D018076:DNA, Complementary / Q000235:genetics; D019281:Dimerization; D004789:Enzyme Activation; D005091:Exons / Q000235:genetics*; D005246:Feedback; D005347:Fibroblasts; D051380:GRB2 Adaptor Protein; D006801:Humans; D016350:Leucine Zippers / Q000235:genetics / Q000502:physiology*; D015514:Oncogene Proteins, Fusion / Q000737:chemistry / Q000235:genetics* / Q000502:physiology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D000090063:Proto-Oncogene Mas; D051381:Rats; D011916:Rats, Inbred F344; D011993:Recombinant Fusion Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D017384:Sequence Deletion; D015398:Signal Transduction / Q000502:physiology*; D013329:Structure-Activity Relationship; D014162:Transfection; D014410:Tumor Stem Cell Assay
D048868:Adaptor Proteins, Signal Transducing; D018076:DNA, Complementary; C098587:GAB1 protein, human; D051380:GRB2 Adaptor Protein; C495948:GRB2 protein, human; C490896:Gab1 protein, rat; C495950:Grb2 protein, rat; C000715470:MAS1 protein, human; D015514:Oncogene Proteins, Fusion; D010750:Phosphoproteins; D011506:Proteins; D000090063:Proto-Oncogene Mas; D011993:Recombinant Fusion Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases