Involvement of Shc and Cbl-PI 3-kinase in Lyn-dependent proliferative signaling pathways for G-CSF.
Granulocyte colony-stimulating factor (G-CSF) is the major hematopoietic factor which controls the production and differentiation of granulocytes. The G-CSF receptor (G-CSFR) belongs to the superfamily of the cytokine receptors, which transduce signals via the activation of cytosolic protein tyrosine kinases (PTK). To determine the role of specific PTK in G-CSF signaling we expressed the human G-CSFR in cell lines derived from DT40 B cells, which lack either the Src-related Lyn or Syk. Wild-type (wt) and syk-deficient cells underwent increased DNA synthesis in response to G-CSF; lyn-deficient cells did not. The purpose of these studies is to identify Lyn's downstream effectors in mediating DNA synthesis. While G-CSF stimulated Ras activity in all cell lines, G-CSF failed to induce the tyrosine phosphorylation of Shc in lyn-deficient cells. G-CSF induced a statistically significant activation of Erk1/Erk2 Kinase or p90Rsk only in the wt cells. G-CSF induced the tyrosine phosphorylation of Cbl and increased activity of PI 3-kinase in wild-type and syk-deficient, but non in lyn-deficient, cells. Inhibition of Shc by over-expression of its SH2 or PTB domains or PI 3-kinase by either treatment with wortmannin or expression of the CblY731F mutant decreased G-CSF-induced DNA synthesis. Thus, the Lyn, Cbl-PI 3-kinase, and Shc/non-Ras-dependent pathways correlate with the ability of cells to respond to G-CSF with increased DNA synthesis.
Grishin
A
A
Division of Hematology-Oncology, Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, PA 15213, USA.
Sinha
S
S
Roginskaya
V
V
Boyer
M J
MJ
Gomez-Cambronero
J
J
Zuo
S
S
Kurosaki
T
T
Romero
G
G
Corey
S J
SJ
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002645:Chickens; D004247:DNA / Q000096:biosynthesis; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D011494:Protein Kinases / Q000502:physiology; D011506:Proteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D050721:Proto-Oncogene Proteins c-cbl; D019893:Ribosomal Protein S6 Kinases; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D044767:Ubiquitin-Protein Ligases; D018631:ras Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000502:physiology*
D048868:Adaptor Proteins, Signal Transducing; D033942:Adaptor Proteins, Vesicular Transport; D011506:Proteins; D011518:Proto-Oncogene Proteins; C528024:SHC1 protein, human; D055765:Shc Signaling Adaptor Proteins; D000071425:Src Homology 2 Domain-Containing, Transforming Protein 1; D016179:Granulocyte Colony-Stimulating Factor; D006160:Guanosine Triphosphate; D004247:DNA; D050721:Proto-Oncogene Proteins c-cbl; D044767:Ubiquitin-Protein Ligases; D011494:Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases; D019893:Ribosomal Protein S6 Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D018631:ras Proteins; C067419:CBL protein, human