The mitogenic signaling pathway for fibroblast growth factor-2 involves the tyrosine phosphorylation of cyclin D2 in MCF-7 human breast cancer cells.
Fibroblast growth factor-2 (FGF-2) is mitogenic for the human breast cancer cell line MCF-7; here we investigate some of the signaling pathways subserving this activity. FGF-2 stimulation of MCF-7 cells resulted in a global increase of intracellular tyrosine phosphorylation of proteins, particularly FGF receptor substrate-2, the protooncogene product Src and the mitogen-activated protein kinase (MAP kinase) cascade. A major increase in the tyrosine phosphorylation of a 30-kDa protein species was also found. This protein was identified as cyclin D2 by mass spectrometry after trypsin digestion. Immunoprecipitation of cyclin D2 and immunoblotting with anti-phosphotyrosine antibodies confirmed that the tyrosine phosphorylation of cyclin D2 was indeed induced by FGF-2 stimulation. In addition, pharmacological inhibition of Src (with herbimycin A and PP2), and of the MAP kinase cascade (with PD98059), confirmed that Src activity is required for the FGF-2-induced phosphorylation of cyclin D2 whereas MAP kinase activity is not. Thus, tyrosine phosphorylation of cyclin D2 may be a key regulatory target for FGF-2 signaling.
Equipe Facteurs de Croissance, Laboratoire de Biologie du Développement, UPRES-EA1033, Unviersité des Sciences et Technologies de Lille, Villeneuve d'Ascq, France.
A
A
Vercoutter-Edouart
J
J
Lemoine
C E
CE
Smart
V
V
Nurcombe
B
B
Boilly
J
J
Peyrat
H
H
Hondermarck
D048868:Adaptor Proteins, Signal Transducing; D000595:Amino Acid Sequence; D015153:Blotting, Western; D001943:Breast Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D056742:Cyclin D2; D016213:Cyclins / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D016222:Fibroblast Growth Factor 2 / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D008934:Mitogens / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D019000:Phosphotyrosine / Q000378:metabolism*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000037:antagonists & inhibitors / Q000378:metabolism; D017468:Receptors, Fibroblast Growth Factor / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014407:Tumor Cells, Cultured
D048868:Adaptor Proteins, Signal Transducing; C080336:CCND2 protein, human; D056742:Cyclin D2; D016213:Cyclins; C106534:FRS2 protein, human; D008565:Membrane Proteins; D008934:Mitogens; D010750:Phosphoproteins; D017468:Receptors, Fibroblast Growth Factor; D016222:Fibroblast Growth Factor 2; D019000:Phosphotyrosine; D016392:Proto-Oncogene Proteins pp60(c-src); D020928:Mitogen-Activated Protein Kinases