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The antigen receptors on mature and immature T lymphocytes are coupled to phosphatidylcholine‐specific phospholipase D activation
Author(s) -
REID P. A.,
GARDNER * S. D.,
WILLIAMS D. M.,
HARNETT† M. M.
Publication year - 1997
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1046/j.1365-2567.1997.00150.x
Subject(s) - phospholipase d , biology , microbiology and biotechnology , pld2 , tyrosine phosphorylation , phospholipase c , t cell , t cell receptor , signal transduction , phosphatidylinositol , cd3 , antigen , phosphatidylcholine , biochemistry , immunology , immune system , phospholipid , cd8 , membrane
Phosphatidylcholine–phospholipase D has been proposed to play a key role in the transduction of the proliferative responses of a wide range of mitogens and growth factors. We now report that the antigen receptors on T lymphocytes derived from human tonsillar or murine splenic preparations are coupled to phosphatidylcholine (PtdCho)–phospholipase D (PLD) activation following stimulation of these T cells with anti‐CD3 antibodies. However, since we also demonstrate that the antigen receptors on murine thymocytes are coupled to PtdCho–PLD activation, we propose that it is unlikely that this PLD pathway plays a central role in the transduction of T‐cell proliferative responses, but rather, may be involved in either driving cells into cycle or maintaining cell cycle progression, processes required both for proliferation and activation‐induced cell death. Whilst the molecular mechanisms underlying T‐cell receptor (TCR)‐coupling to PtdCho–PLD activation in these cells have not been fully defined, kinetics studies and experiments using pharmacological inhibitors of protein tyrosine phosphatases (PTPases) and reconstituting CD3‐coupled PtdCho–PLD activity in streptolysin‐O permeabilized cells, suggest that the TCR/CD3 complex, under optimal conditions of activation, may be predominantly coupled to PtdCho–PLD activation downstream of tyrosine phosphorylation of phospholipase C‐ γ (PLC‐ γ ), phosphatidylinositol (PtdIns)P 2 hydrolysis, calcium mobilization and protein kinase C (PKC) activation.