Effect of nonhydrolyzable guanosine phosphate on IgE-mediated activation of phospholipase C and histamine release from rodent mast cells.
Rat mast cells and bone marrow-derived mouse mast cells (BMMC) were sensitized with mouse IgE mAb, and permeabilized by ATP to introduce guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S) and/or guanosine-5'-O-(2-thiodiphosphate) (GDP beta S) into the cells. After ATP-induced lesions were resealed with Mg2+, the cells were challenged by Ag to determine the effect of the nonhydrolyzable guanosine phosphate on Ag-induced hydrolysis of phosphoinositides and histamine release. Introduction of GTP gamma S into permeabilized rat mast cells or BMMC, followed by exposure of the cells to extracellular Ca2+, resulted in histamine release, but failed to induce hydrolysis of phosphoinositides. It was also found that introduction of GTP gamma S into the cells did not synergistically enhance Ag-induced histamine release. Introduction of GDP beta S into sensitized BMMC inhibited the GTP gamma S-dependent, Ca2+-induced histamine release but failed to inhibit Ag-induced histamine release. The results suggest that GTP gamma S-dependent, Ca2+-induced histamine release and Ag-induced histamine release go through independent biochemical pathways. It was also found that introduction of GTP gamma S or GDP beta S into sensitized BMMC neither enhanced nor inhibited Ag-induced formation of inositol phosphates. These results together with previous findings that pretreatment of BMMC with either pertussis toxin or cholera toxin does not affect Ag-induced hydrolysis of phosphoinositides, indicate that a G protein is not involved in the transduction of IgE-mediated triggering signals to phospholipase C in rodent mast cells.
Saito
H
H
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21239.
Ishizaka
K
K
Ishizaka
T
T
D000362:Agar; D000818:Animals; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004140:Dinitrophenols / Q000276:immunology; D004789:Enzyme Activation / Q000187:drug effects; D006150:Guanine Nucleotides / Q000378:metabolism / Q000494:pharmacology*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D006241:Haptens / Q000276:immunology; D006636:Histamine Release / Q000187:drug effects*; D006868:Hydrolysis; D007073:Immunoglobulin E / Q000502:physiology*; D008407:Mast Cells / Q000201:enzymology* / Q000276:immunology / Q000378:metabolism; D051379:Mice; D008808:Mice, Inbred CBA; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D012709:Serum Albumin / Q000276:immunology; D013873:Thionucleotides / Q000494:pharmacology; D010738:Type C Phospholipases / Q000378:metabolism*
D004140:Dinitrophenols; D006150:Guanine Nucleotides; D006241:Haptens; D010716:Phosphatidylinositols; D012709:Serum Albumin; D013873:Thionucleotides; C058064:dinitrophenyl-human serum albumin conjugate; D006153:Guanosine Diphosphate; D007073:Immunoglobulin E; C023427:guanosine 5'-O-(2-thiodiphosphate); D006160:Guanosine Triphosphate; D000362:Agar; D000242:Cyclic AMP; D010738:Type C Phospholipases