Structural and functional basis of a role for CRKL in a fibroblast growth factor 8-induced feed-forward loop.
The adapter protein CRKL is required for the normal development of multiple tissues that rely on fibroblast growth factor 8 (FGF8). The precise role of CRKL in receptor signaling has been unclear, however. To address this issue, we first modeled the three-dimensional structure of CRKL by molecular dynamics. By taking ... advantage of structural simulations, we performed in silico analysis of the interactions of the autophosphorylation sites of FGR receptor 1 (FGFR1) with the SH2 domain of CRKL or a highly related protein, CRK. As predicted by simulations, we confirm the specific physical interaction of phosphorylated Y463 (pY463) in FGFR1 with the CRKL SH2 domain at an affinity approximately 30-fold stronger than that of CRK. We also provide evidence that interactions outside of the core YXXP motif have a significant impact on physical association, which is consistent with predictions from molecular-dynamics simulations. Furthermore, we identify CRKL as an essential component of an FGF8-induced feed-forward loop permissive for efficient activation of the mitogen-activated protein kinase Erk1/2, as well as FGF8-induced anchorage-independent cell growth, using Crkl-deficient cells or a pY463 synthetic peptide. Although many cells generally require cell-matrix adhesion, our results demonstrate that CRKL permits cells to bypass the strict need for adhesion in response to FGF8 through direct interaction with receptor.
Mesh Terms:
Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Animals, Cell Adhesion, Cell Proliferation, Computational Biology, Computer Simulation, Feedback, Physiological, Fibroblast Growth Factor 8, Humans, MAP Kinase Kinase 1, Mice, Models, Biological, Models, Molecular, Molecular Sequence Data, Monomeric GTP-Binding Proteins, Nuclear Proteins, Peptides, Phosphorylation, Phosphotyrosine, Protein Binding, Proto-Oncogene Proteins c-crk, Receptor, Fibroblast Growth Factor, Type 1, Structure-Activity Relationship, raf Kinases, src Homology Domains
Adaptor Proteins, Signal Transducing, Amino Acid Sequence, Animals, Cell Adhesion, Cell Proliferation, Computational Biology, Computer Simulation, Feedback, Physiological, Fibroblast Growth Factor 8, Humans, MAP Kinase Kinase 1, Mice, Models, Biological, Models, Molecular, Molecular Sequence Data, Monomeric GTP-Binding Proteins, Nuclear Proteins, Peptides, Phosphorylation, Phosphotyrosine, Protein Binding, Proto-Oncogene Proteins c-crk, Receptor, Fibroblast Growth Factor, Type 1, Structure-Activity Relationship, raf Kinases, src Homology Domains
Mol. Cell. Biol.
Date: Jun. 01, 2009
PubMed ID: 19307307
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