Abstract
The NF-kappaB activation pathway induced by T cell costimulation uses various molecules including Vav1 and protein kinase C (PKC)theta. Because Vav1 inducibly associates with further proteins including phospholipase C (PLC)gamma1 and Src homology 2 domain-containing leukocyte phosphoprotein of 76 kDa (SLP-76), we investigated their role for NF-kappaB activation in Jurkat leukemia T cell lines deficient for expression of these two proteins. Cells lacking SLP-76 or PLCgamma1 failed to activate NF-kappaB in response to T cell costimulation. In contrast, replenishment of SLP-76 or PLCgamma1 expression restored CD3/CD28-induced IkappaB kinase (IKK) activity as well as NF-kappaB DNA binding and transactivation. PKCtheta activated NF-kappaB in SLP-76- and PLCgamma1-deficient cells, showing that PKCtheta is acting further downstream. In contrast, Vav1-induced NF-kappaB activation was normal in SLP-76(-) cells, but absent in PLCgamma1(-) cells. CD3/CD28-stimulated recruitment of PKCtheta and IKKgamma to lipid rafts was lost in SLP-76- or PLCgamma1-negative cells, while translocation of Vav1 remained unaffected. Accordingly, recruitment of PKCtheta to the immunological synapse strictly relied on the presence of SLP-76 and PLCgamma1, but synapse translocation of Vav1 identified in this study was independent from both proteins. These results show the importance of SLP-76 and PLCgamma1 for NF-kappaB activation and raft translocation of PKCtheta and IKKgamma.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adaptor Proteins, Signal Transducing
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CD28 Antigens / pharmacology
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CD3 Complex / pharmacology
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Cell Cycle Proteins*
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Humans
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I-kappa B Kinase
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Isoenzymes / biosynthesis
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Isoenzymes / genetics
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Isoenzymes / metabolism*
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Isoenzymes / physiology*
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Jurkat Cells
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Lymphocyte Activation* / genetics
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Membrane Microdomains / enzymology*
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Membrane Microdomains / genetics
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NF-kappa B / biosynthesis
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NF-kappa B / metabolism*
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Phospholipase C gamma
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Phosphoproteins / deficiency
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Phosphoproteins / genetics
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Phosphoproteins / physiology*
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Protein Kinase C / biosynthesis
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Protein Kinase C / genetics
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Protein Kinase C / metabolism*
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Protein Kinase C-theta
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Protein Serine-Threonine Kinases / metabolism
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Protein Transport / genetics
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Protein Transport / immunology
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Proto-Oncogene Proteins / biosynthesis
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Proto-Oncogene Proteins / metabolism
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Proto-Oncogene Proteins c-vav
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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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Transfection
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Type C Phospholipases / genetics
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Type C Phospholipases / physiology*
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src Homology Domains / genetics
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src Homology Domains / immunology*
Substances
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Adaptor Proteins, Signal Transducing
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CD28 Antigens
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CD3 Complex
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Cell Cycle Proteins
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Isoenzymes
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NF-kappa B
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Phosphoproteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-vav
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SLP-76 signal Transducing adaptor proteins
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VAV1 protein, human
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Protein Serine-Threonine Kinases
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CHUK protein, human
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I-kappa B Kinase
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IKBKB protein, human
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IKBKE protein, human
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PRKCQ protein, human
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Protein Kinase C
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Protein Kinase C-theta
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Type C Phospholipases
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Phospholipase C gamma