Phosphorylation of the gamma chain of the high affinity receptor for immunoglobulin E by receptor-associated protein kinase C-delta.
The gamma chain of the high affinity receptor for immunoglobulin E is a member of the T-cell antigen receptor zeta chain family and a functional subunit common to both T-cell and Fc receptors. Here we report that the gamma chain is phosphorylated on threonine in response to protein kinase C activation. Furthermore, the threonine phosphorylation of the gamma chain correlates with the endocytosis of this receptor. We identified a receptor-associated kinase as the calcium-independent protein kinase C-delta and found that it associates with the carboxyl-terminal cytoplasmic domain of the beta chain. In addition, protein kinase C-delta was the only isozyme capable of phosphorylating the gamma chain in vitro. These findings provide evidence for the functional role of protein kinase C-delta in early signal transduction events in the mast cell and suggest a more general mechanism of activation for receptors that share subunits of the zeta chain family.
Germano
P
P
Section on Chemical Immunology, NIAMSD, National Institutes of Health, Bethesda, Maryland 20892.
Gomez
J
J
Kazanietz
M G
MG
Blumberg
P M
PM
Rivera
J
J
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004705:Endocytosis; D004789:Enzyme Activation; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008301:Maleimides / Q000494:pharmacology; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051745:Protein Kinase C-delta; D051381:Rats; D017455:Receptors, IgE / Q000737:chemistry / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013912:Threonine / Q000378:metabolism; D014407:Tumor Cells, Cultured
D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; D017455:Receptors, IgE; D013912:Threonine; C497260:Prkcd protein, rat; D011493:Protein Kinase C; D051745:Protein Kinase C-delta; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium; C064755:Ro 31-7549