Tyrosine phosphorylation and translocation of the c-cbl protein after activation of tyrosine kinase signaling pathways.
The c-cbl protooncogene product (c-Cbl) is a 120-kDa protein that has been shown to bind to the Src homology 3 domains of various proteins, suggesting its involvement in signal transduction pathways. We identified one of the most prominent tyrosine-phosphorylated proteins in Fc gamma receptor (Fc gamma R)-stimulated macrophages to be c-Cbl. Tyrosine phosphorylation of c-Cbl occurred within 20 s after stimulation and reached maximum levels within 3-5 min. c-Cbl was also tyrosine-phosphorylated in epidermal growth factor (EGF) receptor-overexpressing cells upon EGF stimulation, in macrophages in response to CSF-1 treatment, and in v-src transformed cells. Furthermore, we found that c-Cbl associated with these kinases in vivo. In vitro, c-Cbl bound to the Src homology 3 domains of Src, Fyn, and Lyn in both unstimulated and Fc gamma R-stimulated macrophages. Examination of cells by immunofluorescence revealed that c-Cbl is diffusely distributed in the cytoplasm in both unstimulated macrophages and EGF receptor-overexpressing cells and translocated to a more specific compartment of the cell, consistent with the trans-Golgi region, following Fc gamma R clustering and EGF stimulation, respectively. These results suggest that c-Cbl is involved in the signaling pathways utilized by different types of tyrosine kinases.
Tanaka
S
S
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Neff
L
L
Baron
R
R
Levy
J B
JB
D000818:Animals; D001692:Biological Transport; D002478:Cells, Cultured; D004789:Enzyme Activation; D017737:Macrophages, Peritoneal / Q000201:enzymology / Q000378:metabolism; D051379:Mice; D010766:Phosphorylation; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D050721:Proto-Oncogene Proteins c-cbl; D017452:Receptors, IgG / Q000378:metabolism; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases
D011518:Proto-Oncogene Proteins; D017452:Receptors, IgG; D014443:Tyrosine; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D011505:Protein-Tyrosine Kinases; C493849:Cbl protein, mouse