CKIP-1 is an intrinsic negative regulator of T-cell activation through an interaction with CARMA1.
The transcription factor NF-κB plays a key regulatory role in lymphocyte activation and generation of immune response. Stimulation of T cell receptor (TCR) induces phosphorylation of CARMA1 by PKCθ, resulting in formation of CARMA1-Bcl10-MALT1 (CBM) complex at lipid rafts and subsequently leading to NF-κB activation. While many molecular events leading to NF-κB activation have been reported, it is less understood how this activation is negatively regulated. We performed a cell-based screening for negative regulators of TCR-mediated NF-κB activation, using mutagenesis and complementation cloning strategies. Here we show that casein kinase-2 interacting protein-1 (CKIP-1) suppresses PKCθ-CBM-NF-κB signaling. We found that CKIP-1 interacts with CARMA1 and competes with PKCθ for association. We further confirmed that a PH domain of CKIP-1 is required for association with CARMA1 and its inhibitory effect. CKIP-1 represses NF-κB activity in unstimulated cells, and inhibits NF-κB activation induced by stimulation with PMA or constitutively active PKCθ, but not by stimulation with TNFα. Interestingly, CKIP-1 does not inhibit NF-κB activation induced by CD3/CD28 costimulation, which caused dissociation of CKIP-1 from lipid rafts. These data suggest that CKIP-1 contributes maintenance of a resting state on NF-κB activity or prevents T cells from being activated by inadequate signaling. In conclusion, we demonstrate that CKIP-1 interacts with CARMA1 and has an inhibitory effect on PKCθ-CBM-NF-κB signaling.
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Takashi
T
Sakamoto
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Masayuki
M
Kobayashi
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Kohei
K
Tada
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Masanobu
M
Shinohara
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Katsuhiro
K
Io
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Kayoko
K
Nagata
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Fumie
F
Iwai
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Yoko
Y
Takiuchi
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Yasuyuki
Y
Arai
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Kouhei
K
Yamashita
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Keisuke
K
Shindo
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Norimitsu
N
Kadowaki
Laboratory of Viral Pathogenesis, Institute for Virus Research, Kyoto University, Kyoto, Japan.
Yoshio
Y
Koyanagi
Department of Hematology and Oncology, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
Akifumi
A
Takaori-Kondo
D053468:CARD Signaling Adaptor Proteins / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006162:Guanylate Cyclase / Q000378:metabolism*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes / Q000378:metabolism; D019169:Jurkat Cells; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D021962:Membrane Microdomains / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D000074121:Protein Kinase C-theta; D017434:Protein Structure, Tertiary; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D053468:CARD Signaling Adaptor Proteins; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007527:Isoenzymes; D016328:NF-kappa B; C408877:PLEKHO1 protein, human; C076233:PRKCQ protein, human; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; C426242:CARD11 protein, human; D006162:Guanylate Cyclase; D013755:Tetradecanoylphorbol Acetate