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Published on: October 30, 2012
FRS2-independent GRB2 interaction with FGFR2 is not required for embryonic development
James F Clark1, Philippe Soriano1
1Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
Abstract:
FGF activation is known to engage canonical signals, including ERK/MAPK and PI3K/AKT, through various effectors including FRS2 and GRB2. Fgfr2FCPG/FCPG mutants that abrogate canonical intracellular signaling exhibit a range of mild phenotypes but are viable, in contrast to embryonic lethal Fgfr2-/- mutants. GRB2 has been reported to interact with FGFR2 through a non-traditional mechanism, by binding to the C-terminus of FGFR2 independently of FRS2 recruitment. To investigate whether this interaction provides functionality beyond canonical signaling, we generated mutant mice harboring a C-terminal truncation (T). We found that Fgfr2T/T mice are viable and have no distinguishable phenotype, indicating that GRB2 binding to the C-terminal end of FGFR2 is not required for development or adult homeostasis. We further introduced the T mutation on the sensitized FCPG background but found that Fgfr2FCPGT/FCPGT mutants did not exhibit significantly more severe phenotypes. We therefore conclude that, although GRB2 can bind to FGFR2 independently of FRS2, this binding does not have a critical role in development or homeostasis.
Insights
Fibroblast Growth Factor Receptor 2 (FGFR2) C-terminal binding to GRB2 is not essential for mouse development or homeostasis. This non-canonical signaling pathway does not significantly impact FGFR2 function in vivo.
Area of Science:
- Cellular Biology
- Molecular Biology
- Genetics
Background:
- Fibroblast Growth Factor (FGF) signaling pathways, including ERK/MAPK and PI3K/AKT, are crucial for cellular processes.
- FGFR2 interacts with signaling molecules like FRS2 and GRB2.
- Canonical FGFR2 signaling is vital, as Fgfr2-/- mutants are embryonically lethal.
Purpose of the Study:
- To investigate the functional significance of GRB2 binding to the FGFR2 C-terminus independently of FRS2.
- To determine if this non-canonical interaction plays a role in development and homeostasis.
Main Methods:
- Generation of mutant mice with a C-terminal truncation (T) in FGFR2 (Fgfr2T/T).
- Analysis of Fgfr2T/T mice for developmental and homeostatic phenotypes.
- Introduction of the T mutation into a sensitized FCPG background (Fgfr2FCPGT/FCPGT) to assess synergistic effects.
Main Results:
- Fgfr2T/T mice were viable and displayed no discernible phenotypes, indicating GRB2 C-terminal binding is not essential for development or homeostasis.
- Fgfr2FCPGT/FCPGT mutants did not show significantly more severe phenotypes compared to FCPG mutants.
- These findings suggest the non-canonical GRB2-FGFR2 interaction lacks critical in vivo functionality.
Conclusions:
- GRB2 binding to the FGFR2 C-terminus, independent of FRS2, is dispensable for mouse development and adult homeostasis.
- The non-canonical interaction between GRB2 and FGFR2 does not appear to contribute significantly to FGFR2-mediated biological functions.
- Further research may explore other potential roles or contexts for this interaction.
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