Structural and functional basis of a role for CRKL in a fibroblast growth factor 8-induced feed-forward loop

Mol Cell Biol. 2009 Jun;29(11):3076-87. doi: 10.1128/MCB.01686-08. Epub 2009 Mar 23.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Amino Acid Sequence
  • Animals
  • Cell Adhesion / drug effects
  • Cell Proliferation / drug effects
  • Computational Biology
  • Computer Simulation
  • Feedback, Physiological / drug effects*
  • Fibroblast Growth Factor 8 / pharmacology*
  • Humans
  • MAP Kinase Kinase 1 / metabolism
  • Mice
  • Models, Biological
  • Models, Molecular
  • Molecular Sequence Data
  • Monomeric GTP-Binding Proteins / metabolism
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / metabolism*
  • Peptides / chemistry
  • Phosphorylation / drug effects
  • Phosphotyrosine / metabolism
  • Protein Binding / drug effects
  • Proto-Oncogene Proteins c-crk / chemistry
  • Proto-Oncogene Proteins c-crk / metabolism
  • Receptor, Fibroblast Growth Factor, Type 1 / metabolism
  • Structure-Activity Relationship
  • raf Kinases / metabolism
  • src Homology Domains


  • Adaptor Proteins, Signal Transducing
  • CRK protein, human
  • CRKL protein
  • Nuclear Proteins
  • Peptides
  • Proto-Oncogene Proteins c-crk
  • Fibroblast Growth Factor 8
  • Phosphotyrosine
  • Receptor, Fibroblast Growth Factor, Type 1
  • raf Kinases
  • MAP Kinase Kinase 1
  • Monomeric GTP-Binding Proteins