CD45-deficient RBL-2H3 cells. Cellular response to Fc epsilon R- and ionophore-induced stimulation.
The CD45 protein is a transmembrane tyrosine phosphatase that is required for normal T and B cell receptor-mediated signaling. In order to study the function of this phosphatase in mast cells, we have isolated a CD45-deficient variant from the rat basophilic leukemia cell line (RBL-2H3), a tumor analog of mucosal mast cells. The secretory response as well as the inositol 1,4,5-triphosphate (InsP3) formation to Fc epsilon RI and ionophore stimuli were similar in the RBL-2H3 cell line and its derived CD45-deficient subpopulation. However, pretreatment with the phorbol ester TPA, which directly activates protein kinase C (PKC), caused a marked increase in mediator release and InsP3 production in the CD45-deficient variant compared to the parental RBL-2H3 cells. These findings suggest that CD45 might directly or indirectly modify the activity of PKC or the InsP3-dephosphorylating phosphatase.
Schneider
H
H
Paul-Ehrlich-Institute, Langen, FRG.
Korn
M
M
Haustein
D
D
D000818:Animals; D015153:Blotting, Western; D005434:Flow Cytometry; D007295:Inositol Phosphates / Q000378:metabolism; D015759:Ionomycin / Q000494:pharmacology*; D017493:Leukocyte Common Antigens / Q000502:physiology*; D008407:Mast Cells / Q000276:immunology*; D011233:Precipitin Tests; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D051381:Rats; D017455:Receptors, IgE / Q000502:physiology*; D015290:Second Messenger Systems / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
D007295:Inositol Phosphates; D017455:Receptors, IgE; D015759:Ionomycin; D017493:Leukocyte Common Antigens; D017027:Protein Tyrosine Phosphatases; D001619:beta-N-Acetylhexosaminidases; D013755:Tetradecanoylphorbol Acetate