Sprouty2 binds Grb2 at two different proline-rich regions, and the mechanism of ERK inhibition is independent of this interaction.
Sprouty2 has been widely implicated in the negative regulation of the fibroblast growth factor receptor-extracellular regulated kinase (ERK) pathway. Sprouty2 directly interacts with the adapter protein Grb2, member of the receptor tyrosine kinase-induced signaling pathways. In considering the functional role of Grb2, we investigated whether the interaction with this protein was responsible for ERK pathway inhibition. We found that the binding between Sprouty2 and Grb2 is constitutive, independent of Sprouty2 tyrosine phosphorylation, although it is increased when fibroblast growth factor receptor is activated. This connection is mediated by the N-terminal SH3 domain of Grb2 and two Sprouty2 proline-rich stretches (residues 59-64 and 303-307). Most importantly, a double Sprouty2 mutant (hSpry2 P59AP304A), which is unable to bind Grb2, developed at a similar inhibition level of fibroblast growth factor receptor-ERK pathway than that which originated from Sprouty2 wt. These results are evidence that the Sprouty2 mechanism of ERK inhibition is independent of Grb2 binding.
Martínez
Natalia
N
Unidad de Biología Celular, Centro Nacional de Microbiología, Instituto de Salud Carlos III, carretera Majadahonda-Pozuelo, Km 2, Majadahonda-28220, Madrid, Spain.
García-Domínguez
Carlota A
CA
Domingo
Beatriz
B
Oliva
José Luis
JL
Zarich
Natasha
N
Sánchez
Agustín
A
Gutiérrez-Eisman
Silvia
S
Llopis
Juan
J
Rojas
José M
JM
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors*; D031541:Fluorescence Resonance Energy Transfer; D051380:GRB2 Adaptor Protein / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D041681:NIH 3T3 Cells; D011392:Proline / Q000378:metabolism*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D021381:Protein Transport; D015398:Signal Transduction; D018631:ras Proteins / Q000378:metabolism; D018909:src Homology Domains
D051380:GRB2 Adaptor Protein; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C485561:SPRY2 protein, human; D011392:Proline; D048049:Extracellular Signal-Regulated MAP Kinases; D018631:ras Proteins