期刊
JOURNAL OF IMMUNOLOGY
卷 198, 期 10, 页码 3939-3948出版社
AMER ASSOC IMMUNOLOGISTS
DOI: 10.4049/jimmunol.1601078
关键词
-
类别
资金
- National Institutes of Health [R01 AI077610-07, KO8HL093027]
CD4(+) T cells lacking the mTORC1 activator Rheb fail to secrete IFN-gamma under Th1 polarizing conditions. We hypothesized that this phenotype is due to defects in regulation of the canonical Th1 transcription factor T-bet at the level of protein phosphorylation downstream of mTORC1. To test this hypothesis, we employed targeted mass-spectrometry proteomic analysis-multiple reaction monitoring mass spectrometry. We used this method to detect and quantify predicted phosphopeptides derived from T-bet. By analyzing activated murine wild-type and Rheb-deficient CD4(+) T cells, as well as murine CD4(+) T cells activated in the presence of rapamycin, a pharmacologic inhibitor of mTORC1, we were able to identify six T-bet phosphorylation sites. Five of these are novel, and four sites are consistently dephosphorylated in both Rheb-deficient CD4(+) T cells and T cells treated with rapamycin, suggesting mTORC1 signaling controls their phosphorylation. Alanine mutagenesis of each of the six phosphorylation sites was tested for the ability to impair IFN-gamma expression. Single phosphorylation site mutants still support induction of IFN-gamma expression; however, simultaneous mutation of three of the mTORC1-dependent sites results in significantly reduced IFN-gamma expression. The reduced activity of the triple mutant T-bet is associated with its failure to recruit chromatin remodeling complexes to the Ifng gene promoter. These results establish a novel mechanism by which mTORC1 regulates Th1 differentiation, through control of T-bet phosphorylation.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据