DIRECT BINDING OF SHC, GRB2, SHP-2 AND P40 TO THE MURINE GRANULOCYTE-COLONY-STIMULATING FACTOR-RECEPTOR

Granulocyte colony-stimulating factor (G-CSF) mediates the proliferati on, differentiation and activation of cells in the granulocytic lineag e. However; knowledge about the specific signaling pathways utilized b y the G-CSF receptor (G-CSF-R) upon ligand binding remains limited. In this report, we show rapid phosphorylation of Shc upon stimulation of NFS-60 cells with G-CSF, and inducible association of Shc and Grb2 wi th the G-CSF-R in these cells. Using a tyrosine-phosphorylated GST-G-C SF-R fusion we demonstrate that Shc, Grb2 and SHP-2 directly bind the receptor via their respective SH2 domains, suggesting multiple routes of MAPK activation from the G-CSF-R are possible. In addition, we have identified an unknown p40 molecule which is associated with the G-CSF -R transiently following G-CSF stimulation, and a constitutively-assoc iated p37 molecule. (C) 1998 Elsevier Science B.V. All rights reserved .