Activators of protein kinase C down-regulate and phosphorylate the T3/T-cell antigen receptor complex of human T lymphocytes.

AUTOR(ES)

Cantrell, D A

RESUMO

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.

Documentos Relacionados

• CD85/LIR-1/ILT2 and CD152 (Cytotoxic T Lymphocyte Antigen 4) Inhibitory Molecules Down-Regulate the Cytolytic Activity of Human CD4+ T-Cell Clones Specific for Mycobacterium tuberculosis
• T3 glycoprotein is functional although structurally distinct on human T-cell receptor gamma T lymphocytes.
• Interferons alpha and beta down-regulate the expression of basic fibroblast growth factor in human carcinomas.
• Identification of a neural-specific cDNA, NPDC-1, able to down-regulate cell proliferation and to suppress transformation.
• Proline 78 Is Crucial for Human Immunodeficiency Virus Type 1 Nef To Down-Regulate Class I Human Leukocyte Antigen