Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Antigens, CD / biosynthesis
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Antigens, Differentiation, T-Lymphocyte / biosynthesis
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Binding Sites
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Biological Transport
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Biomarkers
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CD28 Antigens / metabolism
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COS Cells
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Carbachol / metabolism
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Carbachol / pharmacology
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Cell Membrane / metabolism
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Chlorocebus aethiops
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Cholinergic Agonists / metabolism
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Cholinergic Agonists / pharmacology
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Cross-Linking Reagents
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Diacylglycerol Kinase / metabolism
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Diacylglycerol Kinase / physiology*
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Diglycerides / pharmacology
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Green Fluorescent Proteins
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Humans
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Jurkat Cells
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Lectins, C-Type
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Luminescent Proteins
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Lymphocyte Activation
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Phosphatidic Acids / metabolism
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Protein Isoforms / metabolism
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Protein Isoforms / physiology
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Protein-Tyrosine Kinases / antagonists & inhibitors
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Protein-Tyrosine Kinases / metabolism
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Receptor, Muscarinic M1
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Receptor-CD3 Complex, Antigen, T-Cell / metabolism
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Receptors, Muscarinic / genetics
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Receptors, Muscarinic / metabolism*
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Signal Transduction / physiology*
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T-Lymphocytes / drug effects
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T-Lymphocytes / metabolism
Substances
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Antigens, CD
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Antigens, Differentiation, T-Lymphocyte
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Biomarkers
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CD28 Antigens
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CD69 antigen
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Cholinergic Agonists
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Cross-Linking Reagents
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Diglycerides
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Lectins, C-Type
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Luminescent Proteins
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Phosphatidic Acids
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Protein Isoforms
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Receptor, Muscarinic M1
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Receptor-CD3 Complex, Antigen, T-Cell
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Receptors, Muscarinic
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Green Fluorescent Proteins
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Carbachol
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Diacylglycerol Kinase
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Protein-Tyrosine Kinases