Synergistic inhibition of T-cell activation by a cell-permeable ZAP-70 mutant and ctCTLA-4.
T-cell activation requires TcR-mediated and co-stimulatory signals. ZAP-70 participates in the initial step of TcR signal transduction, while a co-receptor, CTLA-4, inhibits T-cell activation. In previous studies, the overexpression of a ZAP-70 mutant (ZAP-70-Y319F) inhibited the TcR-induced activation of NFAT and IL-2 production, while Hph-1-ctCTLA-4 prevented allergic inflammation. To develop an effective immunosuppressive protein drug that blocks both TcR-mediated and co-stimulatory signaling pathways, a fusion protein of ZAP-70-Y319F and the Hph-1 protein transduction domain was generated. Hph-1-ZAP-70-Y319F inhibited the phosphorylation of ZAP-70-Tyr319, LAT-Tyr191, and p44/42 MAPK induced by TcR stimulation, NFAT- and AP-1-mediated gene transcription, and the induction of CD69 expression and IL-2 secretion. Hph-1-ZAP-70-Y319F and Hph-1-ctCTLA-4 synergistically inhibited signaling events during T-cell activation. This is the first report to demonstrate the synergistic inhibition of signals transmitted via TcR and its co-stimulatory receptor by cell-permeable forms of intracellular signal mediators.
Kim
Kyun-Do
KD
Department of Biotechnology, Yonsei University, Seodaemun-Gu, Shinchon-Dong 134, Seoul 120-749, Republic of Korea.
Choi
Je-Min
JM
Chae
Wook-Jin
WJ
Lee
Sang-Kyou
SK
D015703:Antigens, CD / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D060908:CTLA-4 Antigen; D002463:Cell Membrane Permeability / Q000276:immunology*; D006801:Humans; D019169:Jurkat Cells; D008213:Lymphocyte Activation; D011948:Receptors, Antigen, T-Cell / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*; D014443:Tyrosine / Q000235:genetics; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000235:genetics / Q000276:immunology* / Q000378:metabolism
D015703:Antigens, CD; D060908:CTLA-4 Antigen; C556706:CTLA4 protein, human; D011948:Receptors, Antigen, T-Cell; D014443:Tyrosine; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human