A highly conserved NTRK3 C-terminal sequence in the ETV6-NTRK3 oncoprotein binds the phosphotyrosine binding domain of insulin receptor substrate-1: an essential interaction for transformation.
Receptor tyrosine kinases are integral components of cellular signaling pathways and are frequently deregulated in malignancies. The NTRK family of neurotrophin receptors mediate neuronal cell survival and differentiation, but altered NTRK signaling has also been implicated in oncogenesis. The ETV6-NTRK3 (EN) gene fusion occurs in human pediatric spindle cell sarcomas and secretory breast carcinoma, and encodes the oligomerization domain of the ETV6 transcription factor fused to the protein-tyrosine kinase domain of NTRK3. The EN protein functions as a constitutively active protein-tyrosine kinase with potent transforming activity in multiple cell lineages, and EN constitutively activates both the Ras-MAPK and phosphatidylinositol 3-kinase-Akt pathways. EN transformation is associated with constitutive tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1). Further, IRS-1 functions as the adaptor protein linking EN to downstream signaling pathways. However, the exact nature of the EN-IRS-1 interaction remains unknown. We now demonstrate that EN specifically binds the phosphotyrosine binding domain of IRS-1 via an interaction at the C terminus of EN. An EN mutant lacking the C-terminal 19 amino acids does not bind IRS-1 and lacks transforming ability. Moreover, expression of an IRS-1 polypeptide containing the phosphotyrosine binding domain acts in a dominant negative manner to inhibit EN transformation, and overexpression of IRS-1 potentiates EN transforming activity. These findings indicate that EN.IRS-1 complex formation through the NTRK3 C terminus is essential for EN transformation.
Lannon
Chris L
CL
Department of Pathology, British Columbia Research Institute for Children's and Women's Health and the University of British Columbia, Vancouver, British Columbia V5Z4H4, Canada.
Martin
Matthew J
MJ
Tognon
Cristina E
CE
Jin
Wook
W
Kim
Seong-Jin
SJ
Sorensen
Poul H B
PH
D000362:Agar / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002454:Cell Differentiation; D002460:Cell Line; D045744:Cell Line, Tumor; D002470:Cell Survival; D002471:Cell Transformation, Neoplastic; D017124:Conserved Sequence; D018076:DNA, Complementary / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000378:metabolism; D005799:Genes, Dominant; D005822:Genetic Vectors; D006801:Humans; D055504:Insulin Receptor Substrate Proteins; D051379:Mice; D008819:Mice, Nude; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D041681:NIH 3T3 Cells; D009474:Neurons / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000737:chemistry* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D019000:Phosphotyrosine / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D050783:Proto-Oncogene Proteins c-ets; D020812:Receptor, trkC / Q000737:chemistry*; D012097:Repressor Proteins / Q000737:chemistry*; D012190:Retroviridae / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013997:Time Factors; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism; D000097764:ETS Translocation Variant 6 Protein
D000362:Agar; D018076:DNA, Complementary; D004268:DNA-Binding Proteins; D055504:Insulin Receptor Substrate Proteins; D015514:Oncogene Proteins, Fusion; D019869:Phosphatidylinositol 3-Kinases; D010750:Phosphoproteins; D019000:Phosphotyrosine; D050783:Proto-Oncogene Proteins c-ets; D020812:Receptor, trkC; D012097:Repressor Proteins; D014443:Tyrosine; D000097764:ETS Translocation Variant 6 Protein; C484319:ETV6-NTRK3 fusion protein, human; C526292:IRS1 protein, human; C526295:Irs1 protein, mouse