| Abstract: |
The transmembrane receptor for immunoglobulin G immune complexes on natural killer (NK) cells and macrophages, FcγIIIA (CD16), mediates cellular activation through a tyrosine kinase-dependent pathway. We show that FcγRIII crosslinking results in activation of the srcrelated kinase p56kkin NK cells and demonstrate a physical association of p56kk with FcγRIIIA in immunoprecipitates from NK cells obtained using anti-FcγRIII antibodies or immune complexes. Our studies show that the ζ chain, the signal transducing subunit of FcγRIIIA and of T cell receptor, associates with p56kk and, in NK cells, is a substrate for this kinase. Such direct association of p56kk with the ζ subunit was confirmed by demonstrating the interaction in heterologous cells transfected with cDNA expressing p56p56kk and ζ. Our findings demonstrate both functional and physical association of p56kk with Fcγ, RIIIA, through direct interaction of the kinase with the ζ and/or the T signal transducer subunits of the receptor. These data suggest a possible mechanism by which activation via Fcγ, RIIIA occurs. © 1993, Rockefeller University Press., All rights reserved. |
| Keywords: |
signal transduction; controlled study; protein phosphorylation; human cell; antigen expression; cells, cultured; enzyme activity; protein tyrosine kinase; phosphorylation; monoclonal antibody; t lymphocyte receptor; lymphocyte activation; amino acid sequence; molecular sequence data; immunoglobulin g; immunoprecipitation; immunoblotting; natural killer cell; killer cells, natural; receptors, igg; cross linking; polyclonal antibody; membrane receptor; lymphocyte specific protein tyrosine kinase p56(lck); lymphoblastoid cell; immunoglobulin fc fragment; protein-tyrosine kinase; human; priority journal; article; support, u.s. gov't, p.h.s.
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