Related Experiment Videos
Biological activity of the thyroid TRK-T3 oncogene requires signalling through Shc
E Roccato1, C Miranda, V Ranzi
1Department of Experimental Oncology, Istituto Nazionale Tumori, Via G. Venezian 1, 20133 Milan, Italy.
Abstract:
The thyroid TRK-T3 oncogene, produced by a chromosomal translocation, is a chimeric, constitutively activated version of the NTRK1/NGF receptor and it is able to transform NIH3T3 cells and differentiate PC12 cells. TRK-T3 oncoprotein triggers multiple signal transduction pathways. Among others, TRK-T3 binds and phosphorylates the Shc and SNT1/FRS2 adaptor proteins both involved in coupling the receptor tyrosine kinase to the mitogen-activated protein kinase pathway by recruiting Grb2/SOS. We were interested in defining the role of Shc in the oncogenesis by TRK-T3. The mutation of TRK-T3 tyrosine 291, docking site for both Shc and FRS2, abrogates the oncogene biological activity. To directly explore the role of Shc we used the ShcY317F mutant, which carries the mutation of a tyrosine residue involved in Grb2 recruitment. We demonstrated that the ShcY317F mutant exerts an inhibitory effect on TRK-T3 transforming activity. Such effect can be modulated by the amount of ShcY317F protein and affects the viability of cells expressing TRK-T3 by means of a mechanism involving apoptosis. Our results indicate a definitive role of the adaptor protein Shc in TRK-T3 transforming activity.
Insights
The adaptor protein Shc plays a critical role in TRK-T3 oncogene activity. A specific Shc mutation inhibits TRK-T3
Area of Science:
- Oncology
- Molecular Biology
- Cell Signaling
Background:
- The TRK-T3 oncogene, a constitutively active NTRK1/NGF receptor variant, drives cellular transformation and activates multiple signaling pathways.
- TRK-T3 interacts with adaptor proteins Shc and SNT1/FRS2, crucial for linking receptor tyrosine kinases to the mitogen-activated protein kinase (MAPK) pathway via Grb2/SOS recruitment.
Purpose of the Study:
- To elucidate the specific role of the Shc adaptor protein in TRK-T3-mediated oncogenesis.
- To investigate the functional consequences of Shc mutations on TRK-T3 transforming activity and cellular viability.
Main Methods:
- Utilized NIH3T3 and PC12 cell lines for transformation and differentiation assays.
- Employed site-directed mutagenesis to create a Shc Y317F mutant, impairing Grb2 binding.
- Assessed the impact of Shc Y317F expression on TRK-T3 transforming potential and induced apoptosis.
Main Results:
- Mutation of TRK-T3 tyrosine 291, a docking site for Shc and FRS2, abolished its oncogenic activity.
- The Shc Y317F mutant demonstrated an inhibitory effect on TRK-T3's transforming capabilities.
- This inhibition was dose-dependent and involved the induction of apoptosis in TRK-T3-expressing cells.
Conclusions:
- The adaptor protein Shc is definitively implicated in the transforming activity of the TRK-T3 oncogene.
- Modulating Shc function, particularly Grb2 recruitment, offers a potential strategy to counteract TRK-T3-driven oncogenesis.