Abstract
Death-associated protein kinase (DAPK) is a unique multidomain kinase acting both as a tumor suppressor and an apoptosis inducer. The molecular mechanism underlying the effector function of DAPK is not fully understood, while the role of DAPK in T lymphocyte activation is mostly unknown. DAPK was activated after TCR stimulation. Through the expression of a dominant-negative and a constitutively active form of DAPK in T cells, we found that DAPK negatively regulated T cell activation. DAPK markedly affected T cell proliferation and IL-2 production. We identified TCR-induced NF-kappaB activation as a target of DAPK. In contrast, IL-1beta- and TNF-alpha-triggered NF-kappaB activation was not affected by DAPK. We further found that DAPK selectively modulated the TCR-induced translocation of protein kinase Ctheta, Bcl-10, and IkappaB kinase into membrane rafts. Notably, the effect of DAPK on the raft entry was specific for the NF-kappaB pathway, as other raft-associated molecules, such as linker for activation of T cells, were not affected. Our results clearly demonstrate that DAPK is a novel regulator targeted to TCR-activated NF-kappaB and T cell activation.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Apoptosis Regulatory Proteins / antagonists & inhibitors
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Apoptosis Regulatory Proteins / genetics
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Apoptosis Regulatory Proteins / physiology*
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Calcium-Calmodulin-Dependent Protein Kinases / antagonists & inhibitors
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Calcium-Calmodulin-Dependent Protein Kinases / genetics
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Calcium-Calmodulin-Dependent Protein Kinases / physiology*
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Cells, Cultured
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Death-Associated Protein Kinases
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Down-Regulation / genetics
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Down-Regulation / immunology*
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Gene Targeting*
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Humans
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Jurkat Cells
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Lymphocyte Activation / genetics
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Lymphocyte Activation / immunology
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Mice
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Mice, Inbred C57BL
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Mice, Transgenic
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NF-kappa B / genetics
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NF-kappa B / metabolism*
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NF-kappa B / physiology
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Phosphorylation
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RNA, Small Interfering / genetics
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Receptors, Antigen, T-Cell / physiology*
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Signal Transduction / genetics
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Signal Transduction / immunology
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T-Lymphocytes / enzymology*
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T-Lymphocytes / immunology
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T-Lymphocytes / metabolism
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Tumor Suppressor Proteins / antagonists & inhibitors
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Tumor Suppressor Proteins / genetics
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Tumor Suppressor Proteins / physiology*
Substances
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Apoptosis Regulatory Proteins
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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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Tumor Suppressor Proteins
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Death-Associated Protein Kinases
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Calcium-Calmodulin-Dependent Protein Kinases