CSF-1 stimulation induces the formation of a multiprotein complex including CSF-1 receptor, c-Cbl, PI 3-kinase, Crk-II and Grb2.
Recently c-Cbl has been reported to be phosphorylated upon CSF-1 stimulation. The product of the c-cbl proto-oncogene (c-Cbl) is a 120 kDa protein harboring several docking sites for Src homology 2 (SH2) domain containing proteins and proline-rich regions that have been shown to allow its constitutive association with the SH3 domains of Grb2. We demonstrate here that CSF-1 exposure of stable transfectant CHO cells expressing the CSF-1 receptor induced the sustained tyrosine phosphorylation of c-Cbl and its subsequent association with Crk-II and the p85 kDa subunit of the PI 3-kinase, while it constitutively associates with Grb2. We demonstrate by in vitro experiments that these associations require the SH2 domain of Crk-II and both the C- and N-terminal SH2 domains of the p85 subunit of the PI 3-kinase. cCbl is the major PI 3-kinase-containing protein in c-Fms expressing CHO cells upon CSF-1 stimulation. Thus c-Cbl behaves as a core protein, allowing the formation of a quaternary complex including, Crk-II, PI 3-kinase and Grb2. We provide evidence that this multiprotein complex can interact with the tyrosine phosphorylated CSF-1 receptor through the unoccupied SH2 domain of Grb2.
Husson
H
H
INSERM U364, Faculte de Medecine, Nice, France.
Mograbi
B
B
Schmid-Antomarchi
H
H
Fischer
S
S
Rossi
B
B
D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D016466:CHO Cells; D006224:Cricetinae; D051380:GRB2 Adaptor Protein; D006801:Humans; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases; D010766:Phosphorylation; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism*; D011485:Protein Binding; D011506:Proteins / Q000378:metabolism*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D050737:Proto-Oncogene Proteins c-crk; D016184:Receptors, Colony-Stimulating Factor / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases; D018909:src Homology Domains
D048868:Adaptor Proteins, Signal Transducing; D051380:GRB2 Adaptor Protein; D016173:Macrophage Colony-Stimulating Factor; D019869:Phosphatidylinositol 3-Kinases; D017853:Phosphotransferases (Alcohol Group Acceptor); D011506:Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D050721:Proto-Oncogene Proteins c-cbl; D050737:Proto-Oncogene Proteins c-crk; D016184:Receptors, Colony-Stimulating Factor; D014443:Tyrosine; D044767:Ubiquitin-Protein Ligases; C495948:GRB2 protein, human; C000715470:MAS1 protein, human; C067419:CBL protein, human