A costimulation-initiated signaling pathway regulates NFATc1 transcription in T lymphocytes.
T cell activation and differentiation is accompanied and mediated by transcriptional reprogramming. The NFATc1 transcription factor is strongly induced upon T cell activation and controls numerous genes involved in the T cell effector function. However, its regulation by physiological stimuli in primary T cells has not been well understood. We previously found that ICOS synergizes with TCR and CD28 to greatly enhance NFATc1 expression in primary T cells. In this study, we have examined the signaling mechanisms whereby costimulation regulates NFATc1 expression. We found that CD28 and ICOS regulate sustained PI3K activity in primary T cells, which is required for NFATc1 up-regulation. CD28 and ICOS costimulation, possibly through Itk, a Tec kinase downstream of the PI3K, enhanced phosphorylation of phospholipase C gamma1 and increased and sustained Ca(2+) flux in T cells. Costimulation of T cells potentiated transcription of the Nfatc1 gene P1 promoter in a PI3K-dependent manner. This work demonstrates an important role for costimulatory receptors in sustaining T cell activation programs leading to Nfatc1 gene transcription and has implications in our understanding of the immune response and tolerance.
Nurieva
Roza I
RI
Department of Immunology, M.D. Anderson Cancer Center, Houston, TX 77030, USA.
Chuvpilo
Sergei
S
Wieder
Eric D
ED
Elkon
Keith B
KB
Locksley
Richard
R
Serfling
Edgar
E
Dong
Chen
C
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology / Q000378:metabolism; D018122:B7-1 Antigen / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051940:B7-2 Antigen / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000276:immunology; D005434:Flow Cytometry; D047468:Immunoprecipitation; D060889:Inducible T-Cell Co-Stimulator Protein; D008213:Lymphocyte Activation / Q000276:immunology; D051379:Mice; D050778:NFATC Transcription Factors / Q000235:genetics / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000276:immunology / Q000378:metabolism; D011401:Promoter Regions, Genetic; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D014158:Transcription, Genetic
D000945:Antigens, Differentiation, T-Lymphocyte; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018106:CD28 Antigens; C556694:Icos protein, mouse; D060889:Inducible T-Cell Co-Stimulator Protein; D050778:NFATC Transcription Factors; D019869:Phosphatidylinositol 3-Kinases