Role of diacylglycerol kinase alpha in the attenuation of receptor signaling.
Diacylglycerol kinase (DGK) is suggested to attenuate diacylglycerol-induced cell responses through the phosphorylation of this second messenger to phosphatidic acid. Here, we show that DGKalpha, an isoform highly expressed in T lymphocytes, translocates from cytosol to the plasma membrane in response to two different receptors known to elicit T cell activation responses: an ectopically expressed muscarinic type I receptor and the endogenous T cell receptor. Translocation in response to receptor stimulation is rapid, transient, and requires calcium and tyrosine kinase activation. DGKalpha-mediated phosphatidic acid generation allows dissociation of the enzyme from the plasma membrane and return to the cytosol, as demonstrated using a pharmacological inhibitor and a catalytically inactive version of the enzyme. The NH(2)-terminal domain of the protein is shown to be responsible for receptor-induced translocation and phosphatidic acid-mediated membrane dissociation. After examining induction of the T cell activation marker CD69 in cells expressing a constitutively active form of the enzyme, we present evidence of the negative regulation that DGKalpha exerts on diacylglycerol-derived cell responses. This study is the first to describe DGKalpha as an integral component of the signaling cascades that link plasma membrane receptors to nuclear responses.
Sanjuán
M A
MA
Department of Immunology and Oncology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas, E-28049 Madrid, Spain.
Jones
D R
DR
Izquierdo
M
M
Mérida
I
I
D000818:Animals; D015703:Antigens, CD / Q000096:biosynthesis; D000945:Antigens, Differentiation, T-Lymphocyte / Q000096:biosynthesis; D001665:Binding Sites; D001692:Biological Transport; D015415:Biomarkers; D018106:CD28 Antigens / Q000378:metabolism; D019556:COS Cells; D002217:Carbachol / Q000378:metabolism / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism; D002522:Chlorocebus aethiops; D018679:Cholinergic Agonists / Q000378:metabolism / Q000494:pharmacology; D003432:Cross-Linking Reagents; D019852:Diacylglycerol Kinase / Q000378:metabolism / Q000502:physiology*; D004075:Diglycerides / Q000494:pharmacology; D049452:Green Fluorescent Proteins; D006801:Humans; D019169:Jurkat Cells; D037181:Lectins, C-Type; D008164:Luminescent Proteins; D008213:Lymphocyte Activation; D010712:Phosphatidic Acids / Q000378:metabolism; D020033:Protein Isoforms / Q000378:metabolism / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D043643:Receptor, Muscarinic M1; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D000099192:CD69 Antigens
D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D015415:Biomarkers; D018106:CD28 Antigens; D002217:Carbachol; D018679:Cholinergic Agonists; D003432:Cross-Linking Reagents; D019852:Diacylglycerol Kinase; D004075:Diglycerides; D049452:Green Fluorescent Proteins; D037181:Lectins, C-Type; D008164:Luminescent Proteins; D010712:Phosphatidic Acids; D020033:Protein Isoforms; D011505:Protein-Tyrosine Kinases; D043643:Receptor, Muscarinic M1; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D011976:Receptors, Muscarinic; D000099192:CD69 Antigens