Open AccessActivators of protein kinase C down-regulate and phosphorylate the T3/T-cell antigen receptor complex of human T lymphocytes.
Author(s) -
Doreen A. Cantrell,
Adelina A. Davies,
Michaël J. Crumpton
Publication year - 1985
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.82.23.8158
Subject(s) - microbiology and biotechnology , antigen , phosphorylation , biology , protein kinase c , lymphoblast , receptor , t cell receptor , biochemistry , t cell , cell culture , immune system , immunology , genetics
As judged by indirect immunofluorescence, phorbol 12,13-dibutyrate and 1-oleoyl-2-acetylglycerol induced a rapid, concentration-dependent decrease of about 50% in the surface expression of the T3 antigen on human T lymphoblasts, and of T3 and the T-cell antigen receptor on HPB-ALL cells. Direct binding experiments using 125I-labeled antibody indicated that the reduction in T3 expression corresponded to a decrease in the number of antigen molecules rather than a change in their affinity. Biochemical analyses revealed that phorbol dibutyrate induced a rapid, prominent phosphorylation of the T3 Mr 26,000 gamma chain and to a lesser extent of the Mr 21,000 delta chain. No phosphorylation of the T3 epsilon chain or of the alpha and beta subunits of the T-cell antigen receptor was detected. The data suggest that protein kinase C induces a phosphorylation of the T3 gamma and delta chains that may lead to the down-regulation of the T3/T-cell antigen receptor complex.