Abstract
Protein kinase C-θ (PKC-θ) is required for activation of the transcription factor NF-κB induced by signaling via the T cell antigen receptor (TCR); however, the direct activator of PKC-θ is unknown. We report that the kinase GLK (MAP4K3) directly activated PKC-θ during TCR signaling. TCR signaling activated GLK by inducing its direct interaction with the upstream adaptor SLP-76. GLK-deficient mice had impaired immune responses and were resistant to experimental autoimmune encephalomyelitis. Consistent with that, people with systemic lupus erythematosus had considerable enhanced GLK expression and activation of PKC-θ and the kinase IKK in T cells, and the frequency of GLK-overexpressing T cells was directly correlated with disease severity. Thus, GLK is a direct activator of PKC-θ, and activation of GLK-PKC-θ-IKK could be used as new diagnostic biomarkers and therapeutic targets for systemic lupus erythematosus.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adult
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Animals
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Autoimmunity / genetics
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Disease Progression
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Female
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Humans
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Isoenzymes / genetics
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Isoenzymes / immunology
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Isoenzymes / metabolism*
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Jurkat Cells
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Lupus Erythematosus, Systemic / immunology*
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Lymphocyte Activation / genetics
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Male
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Mice
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Mice, Knockout
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Middle Aged
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NF-kappa B / immunology
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NF-kappa B / metabolism*
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Protein Kinase C / genetics
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Protein Kinase C / immunology
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Protein Kinase C / metabolism*
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Protein Kinase C-theta
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Protein Serine-Threonine Kinases / genetics
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Protein Serine-Threonine Kinases / immunology
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Protein Serine-Threonine Kinases / metabolism*
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RNA, Small Interfering / genetics
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Receptors, Antigen, T-Cell / immunology
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Receptors, Antigen, T-Cell / metabolism
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Signal Transduction / genetics
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Signal Transduction / immunology
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T-Lymphocytes / immunology
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T-Lymphocytes / metabolism*
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T-Lymphocytes / pathology
Substances
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Isoenzymes
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NF-kappa B
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RNA, Small Interfering
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Receptors, Antigen, T-Cell
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MAP4K3 protein, human
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Protein Serine-Threonine Kinases
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Prkcq protein, mouse
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Protein Kinase C
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Protein Kinase C-theta