Temporal regulation of the IgE-dependent 1,2-diacylglycerol production by tyrosine kinase activation in a rat (RBL 2H3) mast-cell line.
We explored the possible role of tyrosine kinases in the IgE-dependent regulation of 1,2-diacylglycerol (DAG) production in RBL 2H3 cells. When triggered via their high-affinity IgE receptors (Fc epsilon RI), there was a rapid phosphorylation of tyrosine residues on a number of proteins. The phosphorylation of these proteins and ultimately histamine release were inhibited in a concentration-dependent manner by the tyrosine kinase inhibitor, tyrphostin. In cells labelled with [3H]myristic acid, we observed a characteristic biphasic increase in [3H]DAG production. In the presence of tyrosine kinase inhibitor, the initial increase in DAG was still observed, but the secondary increase, which was dependent on phosphatidylcholine-specific phospholipase D (PC-PLD) activation, was completely abolished. Tyrphostin significantly inhibited IgE-dependent activation of PC-PLD, suggesting that PC-PLD activation was regulated by tyrosine phosphorylation. Furthermore, when proteins from RBL 2H3 cells were immunoprecipitated with an anti-phosphotyrosine antibody, PC-PLD activity was recovered from the immunoprecipitated fraction. These results demonstrate that the secondary, but not the initial, phase of 1,2-DAG production in response to Fc epsilon RI aggregation is regulated by the initial activation of tyrosine kinases and that PC-PLD may be regulated directly by this mechanism.
Lin
P
P
Department of Bronchopulmonary Research, Hoffmann-La Roche Inc., Nutley, NJ 07110.
Fung
S J
SJ
Li
S
S
Chen
T
T
Repetto
B
B
Huang
K S
KS
Gilfillan
A M
AM
D000818:Animals; D002396:Catechols / Q000494:pharmacology; D002478:Cells, Cultured; D004075:Diglycerides / Q000096:biosynthesis* / Q000378:metabolism; D004789:Enzyme Activation; D006636:Histamine Release; D007073:Immunoglobulin E / Q000378:metabolism*; D007074:Immunoglobulin G / Q000378:metabolism; D008407:Mast Cells / Q000201:enzymology* / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D010739:Phospholipase D / Q000378:metabolism; D010767:Phosphorylcholine / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011940:Receptor Aggregation; D017455:Receptors, IgE / Q000378:metabolism; D015398:Signal Transduction; D013379:Substrate Specificity; D020032:Tyrphostins
C011439:1,2-diacylglycerol; D002396:Catechols; D004075:Diglycerides; D007074:Immunoglobulin G; D009570:Nitriles; D017455:Receptors, IgE; D020032:Tyrphostins; D010767:Phosphorylcholine; C060152:tyrphostin 47; D007073:Immunoglobulin E; D011505:Protein-Tyrosine Kinases; D010739:Phospholipase D