Scaffolding protein Gab2 mediates differentiation signaling downstream of Fms receptor tyrosine kinase.
Fms is the receptor for macrophage colony-stimulating factor (M-CSF) and contains intrinsic tyrosine kinase activity. Expression of exogenous Fms in a murine myeloid progenitor cell line, FDC-P1 (FD-Fms), results in M-CSF-dependent growth and macrophage differentiation. Previously, we described a 100-kDa protein that was tyrosine phosphorylated upon M-CSF stimulation of FD-Fms cells. In this report, we identify this 100-kDa protein as the recently cloned scaffolding protein Gab2, and we demonstrate that Gab2 associates with several molecules involved in M-CSF signaling, including Grb2, SHP2, the p85 subunit of phosphatidylinositol 3'-kinase, SHIP, and SHC. Tyrosine phosphorylation of Gab2 in response to M-CSF requires the kinase activity of Fms, but not that of Src. Overexpression of Gab2 in FD-Fms cells enhanced both mitogen-activated protein kinase (MAPK) activity and macrophage differentiation, but reduced proliferation, in response to M-CSF. In contrast, a mutant of Gab2 that is unable to bind SHP2 did not potentiate MAPK activity. Furthermore, overexpression of this mutant in FD-Fms cells inhibited macrophage differentiation and resulted in a concomitant increase in growth potential in response to M-CSF. These data indicate that Gab2 is involved in the activation of the MAPK pathway and that the interaction between Gab2 and SHP2 is essential for the differentiation signal triggered by M-CSF.
Liu
Y
Y
Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA. yliu@fhcrc.org
Jenkins
B
B
Shin
J L
JL
Rohrschneider
L R
LR
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D016173:Macrophage Colony-Stimulating Factor / Q000378:metabolism / Q000494:pharmacology; D051379:Mice; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D011817:Rabbits; D016186:Receptor, Macrophage Colony-Stimulating Factor / Q000235:genetics / Q000378:metabolism*; D055765:Shc Signaling Adaptor Proteins; D015398:Signal Transduction / Q000502:physiology*; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; C490895:GAB2 protein, human; C490894:Gab2 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D010750:Phosphoproteins; D011506:Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; C528034:Shc1 protein, mouse; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D014443:Tyrosine; D016173:Macrophage Colony-Stimulating Factor; D016186:Receptor, Macrophage Colony-Stimulating Factor; D019061:src-Family Kinases; D010744:Phosphoric Monoester Hydrolases; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse; C098706:INPPL1 protein, human; D000072183:Phosphatidylinositol-3,4,5-Trisphosphate 5-Phosphatases