Functional expression of the human receptor for colony-stimulating factor 1 (CSF-1) in hamster fibroblasts: CSF-1 stimulates Na+/H+ exchange and DNA-synthesis in the absence of phosphoinositide breakdown.
The human CSF-1 receptor (c-fms protooncogene product) was introduced into CSF-1-unresponsive Chinese hamster lung fibroblasts (CCL39 cell line) in order to study its coupling to biochemical signal-transducing systems and to compare the growth-regulating properties of CSF-1 to those of other growth factors. Independent clones expressing different levels of CSF-1 receptors were isolated and characterized. CSF-1 increased [3H]thymidine incorporation in serum-starved cells and potentiated the mitogenic effects of FGF and thrombin. As already observed for other growth factors activating receptor tyrosine kinases (EGF, FGF, IGF-I), CSF-1 alone did not trigger inositol phosphate formation, but slightly enhanced the activity of phospholipase C agonists (thrombin, A1F4- complex). Activation of the CSF-1 receptor by its ligand was evidenced by the rapid activation of the Na+/H+ exchanger resulting in amiloride-sensitive cytoplasmic alkalinization (0.1-0.2 pH units) within minutes after stimulation. Whereas pertussis toxin does not affect the action of EGF, FGF, or IGF-I in CCL39 cells, it partially inhibited both DNA synthesis reinitiation and activation of Na+/H+ exchange by CSF-1, indicating that the CSF-1 receptor can communicate with a signal-transducing GTP binding protein. A point-mutated form of the c-fms gene product, in which Tyr 969, a residue negatively modulating signal transduction, had been replaced with Phe [fms (F969)], did not generate responses significantly different from those obtained with the wild-type c-fms gene product. In the absence of CSF-1, cells expressing either wild-type or fms (F969) showed a considerably higher basal level of thymidine incorporation and decreased anchorage dependence compared with parental CCL39 cells. Monoclonal antibodies that interfere with signal transduction by the human CSF-1 receptor inhibited both basal [3H]thymidine incorporation and soft agar colony formation, indicating that relaxation of growth control was dependent on CSF-1 receptor expression.
Hartmann
T
T
Centre de Biochimie, CNRS, Nice, France.
Seuwen
K
K
Roussel
M F
MF
Sherr
C J
CJ
Pouysségur
J
J
D000818:Animals; D002352:Carrier Proteins / Q000187:drug effects / Q000378:metabolism*; D002460:Cell Line; D003115:Colony-Stimulating Factors / Q000494:pharmacology*; D004247:DNA / Q000096:biosynthesis* / Q000187:drug effects; D005346:Fibroblast Growth Factors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000494:pharmacology; D016173:Macrophage Colony-Stimulating Factor; D037342:Pertussis Toxin; D010716:Phosphatidylinositols / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D016184:Receptors, Colony-Stimulating Factor; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology*; D017923:Sodium-Hydrogen Exchangers; D013917:Thrombin / Q000494:pharmacology; D014162:Transfection; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D002352:Carrier Proteins; D003115:Colony-Stimulating Factors; D007328:Insulin; D010716:Phosphatidylinositols; D011956:Receptors, Cell Surface; D016184:Receptors, Colony-Stimulating Factor; D011994:Recombinant Proteins; D017923:Sodium-Hydrogen Exchangers; D010566:Virulence Factors, Bordetella; D005346:Fibroblast Growth Factors; D016173:Macrophage Colony-Stimulating Factor; D004247:DNA; D037342:Pertussis Toxin; D013917:Thrombin