Direct and indirect interactions between calcineurin-NFAT and MEK1-extracellular signal-regulated kinase 1/2 signaling pathways regulate cardiac gene expression and cellular growth
Direct and indirect interactions between calcineurin-NFAT and MEK1-extracellular signal-regulated kinase 1/2 signaling pathways regulate cardiac gene expression and cellular growth
复制标题
DOI：
10.1128/mcb.25.3.865-878.2005
复制
发表时间：
2005-02-01
影响因子：
5.3
通讯作者：
Molkentin, JD
中科院分区：
文献类型：
--
作者：
Sanna, B;Bueno, OF;Molkentin, JD
MEK 1是丝裂原活化蛋白激酶（MAPK）级联的一员，可直接激活细胞外信号调节激酶（ERK），诱导转基因小鼠的心脏肥大。钙调神经磷酸酶是一种钙调节的蛋白磷酸酶，其也通过涉及活化T细胞核因子（NFAT）转录因子的活化的直接机制作为心脏肥大性生长的正调节剂发挥作用。在这里，我们确定了钙调神经磷酸酶-NFAT和MEK 1-ERK 1/2信号通路在心肌细胞中是相互依赖的，它们直接共同调节肥大生长反应。例如，钙调磷酸酶A β基因的遗传缺失减少了心脏中由活化的MEK 1转基因引起的肥大反应，而在培养的新生心肌细胞中抑制钙调磷酸酶或NFAT也减弱了由活化的MEK 1驱动的肥大反应。相反，在培养的心肌细胞中靶向抑制MEK 1-ERK 1/2信号转导减弱了由激活的钙调磷酸酶指导的肥大性生长反应。然而，靶向抑制MEK 1-ERK 1/2信号传导并不直接影响钙调神经磷酸酶-NFAT活化。靶向抑制钙调神经磷酸酶-NFAT也不改变MEK 1-ERK 1/2活化。从机制上讲，我们表明，MEK 1-ERK 1/2信号增强NFAT转录活性的钙调磷酸酶独立。不依赖于NFAT核定位的变化，也不依赖于NFAT反式激活潜力的改变。相反，MEK 1-ERK 1/2信号通过间接机制增强NFAT依赖性基因表达，该机制涉及诱导心脏AP-1活性。其作为必要的NFAT相互作用伙伴发挥作用。作为第二种机制，MEK 1-ERK 1/2和钙调神经磷酸酶-NFAT蛋白在心肌细胞中形成复合物，导致NFATc 3在其C末端直接磷酸化。MEK 1-ERK 1/2介导的NFATc 3磷酸化直接增强了其DNA结合活性，而MEK 1-ERK 1/2信号传导的抑制降低了NFATc 3 DNA结合活性。总的来说，这些结果表明，钙调神经磷酸酶-NFAT和MEK 1-ERK 1/2途径构成了心肌细胞中的共依赖信号模块，通过两种不同的机制协调调节生长反应。
MEK1, a member of the mitogen-activated protein kinase (MAPK) cascade that directly activates extracellular signal-regulated kinase (ERK), induces cardiac hypertrophy in transgenic mice. Calcineurin is a calcium-regulated protein phosphatase that also functions as a positive regulator of cardiac hypertrophic growth through a direct mechanism involving activation of nuclear factor of activated T-cell (NFAT) transcription factors. Here we determined that calcineurin-NFAT and MEK1-ERK1/2 signaling pathways are interdependent in cardiomyocytes, where they directly coregulate the hypertrophic growth response. For example, genetic deletion of the calcineurin A P gene reduced the hypertrophic response elicited by an activated MEK1 transgene in the heart, while inhibition of calcineurin or NFAT in cultured neonatal cardiomyocytes also blunted the hypertrophic response driven by activated MEK1. Conversely, targeted inhibition of MEK1-ERK1/2 signaling in cultured cardiomyocytes attenuated the hypertrophic growth response directed by activated calcineurin. However, targeted inhibition of MEK1-ERK1/2 signaling did not directly affect calcineurin-NFAT activation. nor was MEK1-ERK1/2 activation altered by targeted inhibition of calcineurin-NFAT. Mechanistically, we show that MEK1-ERK1/2 signaling augments NFAT transcriptional activity independent of calcineurin. independent of changes in NFAT nuclear localization, and independent of alterations in NFAT transactivation potential. In contrast, MEK1-ERK1/2 signaling enhances NFAT-dependent gene expression through an indirect mechanism involving induction of cardiac AP-1 activity. which functions as a necessary NFAT-interacting partner. As a second mechanism, MEK1-ERK1/2 and calcineurin-NFAT proteins form a complex in cardiac myocytes, resulting in direct phosphorylation of NFATc3 within its C terminus. MEK1-ERK1/2-mediated phosphorylation of NFATc3 directly augmented its DNA binding activity, while inhibition of MEK1-ERK1/2 signaling reduced NFATc3 DNA binding activity. Collectively, these results indicate that calcineurin-NFAT and MEK1-ERK1/2 pathways constitute a codependent signaling module in cardiomyocytes that coordinately regulates the growth response through two distinct mechanisms.