Lobo F M, Zanjani R, Ho N, Chatila T A, Fuleihan R L
Yale Child Health Research Center, Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06520, USA.
J Immunol. 1999 Feb 15;162(4):2057-63.
CD40 ligand (L), FasL, and TNF-alpha are members of the TNF family of cytokines. All are expressed by T lymphocytes shortly after activation but have distinct effector functions. Transcription of these genes can be induced by stimulation of T cells by calcium ionophore alone and requires the calcineurin-dependent transcription factor NF of activated T cells. We have examined a second calcium-dependent signaling pathway, mediated by calcium/calmodulin-dependent kinase IV (CaMKIV) in transcriptional activation of TNF family genes. In reporter gene assays using constructs driven by the promoters of human CD40L, FasL, or TNF-alpha along with vectors expressing constitutively active CaMKIV and calcineurin, we have demonstrated that each promoter is activated by calcineurin and CaMKIV in a synergistic fashion. Furthermore, specific inhibition of CaMKIV by chemical means and by a dominant negative mutant of CaMKIV impairs the ionomycin-induced activity of all three promoters as well as protein expression of CD40L and TNF-alpha. Our results indicate that activation of gene expression by calcineurin and CaMKIV is common to members of the TNF cytokine family.
CD40配体（L）、FasL和肿瘤坏死因子-α（TNF-α）是细胞因子TNF家族的成员。所有这些在T淋巴细胞激活后不久就会表达，但具有不同的效应功能。这些基因的转录可仅通过钙离子载体刺激T细胞来诱导，并且需要活化T细胞的钙调神经磷酸酶依赖性转录因子NF。我们研究了由钙/钙调蛋白依赖性激酶IV（CaMKIV）介导的第二条钙依赖性信号通路在TNF家族基因转录激活中的作用。在使用由人CD40L、FasL或TNF-α启动子驱动的构建体以及表达组成型活性CaMKIV和钙调神经磷酸酶的载体进行的报告基因测定中，我们证明每个启动子都以协同方式被钙调神经磷酸酶和CaMKIV激活。此外，通过化学方法和CaMKIV的显性负突变体对CaMKIV的特异性抑制会损害离子霉素诱导的所有三个启动子的活性以及CD40L和TNF-α的蛋白表达。我们的结果表明，钙调神经磷酸酶和CaMKIV对基因表达的激活是TNF细胞因子家族成员所共有的。
