CrkL is a novel target of Sprouty2 in fibroblast growth factor signaling.
Sprouty, an inhibitor of receptor tyrosine kinase signaling, plays an important role in the regulation of a wide variety of biological processes. Although it is established that the Sprouty inhibitory activity is induced by tyrosine phosphorylation in response to stimuli, its action mechanisms have not been fully elucidated. Here, we report identification of a novel target of Sprouty. We find that Sprouty1 and Sprouty2 bind to the adaptor protein CrkL in a stimulus-dependent manner. Biochemical analyses show that the binding requires tyrosine phosphorylation of Sprouty and that both the SH2 domain and the N-terminal SH3 domain of CrkL are necessary for the binding. In fibroblast growth factor-stimulated NIH3T3 cells, CrkL binding to Sprouty2 occurs concomitantly with tyrosine phosphorylation of Sprouty2, which occurs slowly but is sustained. Importantly, our results show that tyrosine-phosphorylated Sprouty2 suppresses Rap1 activation. These results taken together indicate that Sprouty2 acts as an inhibitor of CrkL-Rap1 signaling.
Department of Cell and Developmental Biology, Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
Takayuki
T
Satoh
Satoru
S
Torii
Kei
K
Nakayama
Eisuke
E
Nishida
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism*; D000818:Animals; D005346:Fibroblast Growth Factors / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008870:Microtubules / Q000378:metabolism; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases; D017434:Protein Structure, Tertiary; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism*; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C082869:CRKL protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D009687:Nuclear Proteins; D017468:Receptors, Fibroblast Growth Factor; D014443:Tyrosine; D005346:Fibroblast Growth Factors; D017346:Protein Serine-Threonine Kinases; C118389:Spry2 protein, mouse; D020827:rap1 GTP-Binding Proteins