Suppression of cyclic GMP-dependent protein kinase is essential to the Wnt/cGMP/Ca2+ pathway
Suppression of cyclic GMP-dependent protein kinase is essential to the Wnt/cGMP/Ca2+ pathway
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DOI：
10.1074/jbc.m603603200
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发表时间：
2006-10-13
影响因子：
4.8
通讯作者：
Wang, Hsien-yu
中科院分区：
文献类型：
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作者：
Ma, Li;Wang, Hsien-yu
寻找新的下游效应器，其响应于Wnt/Frizzled-2途径的激活而感测细胞内Ca 2+和环GMP浓度的变化。Frizzled-2的激活抑制蛋白激酶G活性，同时激活NF-AT依赖性转录。百日咳毒素和G α（t2）或G α（o）表达的敲低消除了这些反应中的每一种。通过激活蛋白激酶G和缓冲细胞内Ca 2+，抑制了响应于Wnt 5a刺激的NF-AT依赖性转录的激活。无论是通过抑制环GMP磷酸二酯酶或通过添加8-溴环GMP的细胞内环GMP的升高被证明激活蛋白激酶G，阻断Ca 2+动员，以及显着减弱激活NF-AT依赖性转录响应Wnt 5a刺激。相反，在Wnt刺激不存在的情况下，RP-8-pCPT-cGMP对蛋白激酶G的化学抑制可引起NF-AT基因转录和Ca 2+动员增加。蛋白激酶G被证明是非经典Wnt-Frizzled-2/cGMP/Ca 2+途径的关键下游效应子。
Novel downstream effectors sensing changes in intracellular concentrations of Ca2+ and cyclic GMP in response to activation of the Wnt/Frizzled-2 pathway were sought. Activation of Frizzled-2 suppressed protein kinase G activity while activating NF-AT-dependent transcription. Each of these responses was abolished by pertussis toxin and by knock-down of the expression of either G alpha(t2) or G alpha(o). Activation of NF-AT-dependent transcription in response to Wnt5a stimulation was suppressed by activation of protein kinase G and by buffering intracellular Ca2+. Elevation of intracellular cyclic GMP either by inhibition of cyclic GMP phosphodiesterase or by addition of 8-bromocyclic GMP was shown to activate protein kinase G, to block Ca2+ mobilization, as well as to markedly attenuate activation of NF-AT-dependent transcription in response to Wnt5a stimulation. Chemical inhibition of protein kinase G by Rp-8-pCPT-cGMP, conversely, was shown to provoke increased NF-AT gene transcription and Ca2+ mobilization in the absence of Wnt stimulation. Protein kinase G is shown to be a critical downstream effector of the noncanonical Wnt-Frizzled-2/cGMP/Ca2+ pathway.