Cellular energetic status supervises the synthesis of bis-diphosphoinositol tetrakisphosphate independently of AMP-activated protein kinase
Cellular energetic status supervises the synthesis of bis-diphosphoinositol tetrakisphosphate independently of AMP-activated protein kinase
复制标题
DOI：
10.1124/mol.107.044628
复制
发表时间：
2008-08-01
影响因子：
3.6
通讯作者：
Shears, Stephen B.
中科院分区：
文献类型：
--
作者：
Choi, Kuicheon;Mollapour, Elahe;Shears, Stephen B.
细胞积极捍卫腺苷核苷酸稳态;细胞内生物传感器检测能量状态的变化并与其他细胞网络通信以启动适应性反应。在这里，我们展示了这个通信过程中的一些新的元素，我们表明，这种网络是由脱靶，一些流行的药理学工具的生物能量效应。用5-氨基咪唑-4-甲酰胺核苷（AICAR）处理细胞，以模拟AMP水平升高，减少了双二磷酸肌醇四磷酸（[PP]（2）-InsP（4））的合成，这是一种在激酶非依赖性反应中磷酸化蛋白质的细胞内信号。这是一种选择性效应;其他肌醇磷酸盐的水平不受AICAR的影响。通过遗传操纵细胞AMP活化蛋白激酶活性，我们发现它并不介导AICAR的这些作用。相反，我们得出结论，腺苷酸平衡恶化的模拟本身抑制了[PP]（2）-InsP（4）的合成。这一结论与我们的研究结果一致，寡霉素升高了细胞[AMP]，并选择性抑制[PP]（2）-InsP（4）的合成，而不影响其他肌醇磷酸。此外，我们报告了2-（2-氯-4-碘苯胺）-N-环丙基甲氧基-3，4-二氟-苯甲酰胺（PD 184352）可减弱高渗应激期间通常观察到的[PP]（2）-InsP（4）水平的短期升高。后者通常被认为是一个精致的特异性丝裂原活化蛋白激酶激酶（MEK）抑制剂，但对MEK或细胞外信号调节激酶的小干扰RNA显示，这种丝裂原活化蛋白激酶途径不参与。相反，我们证明，[PP]（2）-InsP（4）的合成被PD 184352通过其对细胞能量平衡的非特异性作用抑制。另外两种MEK抑制剂，1，4-二氨基-2，3-二氰基-1，4-双（甲硫基）丁二烯（U 0126）和2 '-氨基-3'-甲氧基黄酮（PD 98059），具有类似的脱靶效应。我们的结论是，[PP]（2）-InsP（4）的水平和信号强度受到细胞腺苷酸平衡的监督，标志着信号和生物能量网络之间的新联系。
Cells aggressively defend adenosine nucleotide homeostasis; intracellular biosensors detect variations in energetic status and communicate with other cellular networks to initiate adaptive responses. Here, we demonstrate some new elements of this communication process, and we show that this networking is compromised by off-target, bioenergetic effects of some popular pharmacological tools. Treatment of cells with 5-aminoimidazole-4- carboxamide ribonucleoside (AICAR), so as to simulate elevated AMP levels, reduced the synthesis of bis-diphosphoinositol tetrakisphosphate ([PP](2)-InsP(4)), an intracellular signal that phosphorylates proteins in a kinase-independent reaction. This was a selective effect; levels of other inositol phosphates were unaffected by AICAR. By genetically manipulating cellular AMP-activated protein kinase activity, we showed that it did not mediate these effects of AICAR. Instead, we conclude that the simulation of deteriorating adenosine nucleotide balance itself inhibited [PP](2)-InsP(4) synthesis. This conclusion is consistent with our demonstrating that oligomycin elevated cellular [AMP] and selectively inhibited [PP](2)-InsP(4) synthesis without affecting other inositol phosphates. In addition, we report that the short-term increases in [PP](2)-InsP(4) levels normally seen during hyperosmotic stress were attenuated by 2-(2-chloro-4-iodophenylamino)-N- cyclopropylmethoxy-3,4-difluoro-benzamide (PD184352). The latter is typically considered an exquisitely specific mitogen-activated protein kinase kinase (MEK) inhibitor, but small interfering RNA against MEK or extracellular signal-regulated kinase revealed that this mitogen-activated protein kinase pathway was not involved. Instead, we demonstrate that [PP](2)-InsP(4) synthesis was inhibited by PD184352 through its nonspecific effects on cellular energy balance. Two other MEK inhibitors, 1,4-diamino-2,3-dicyano-1,4-bis(methylthio) butadiene (U0126) and 2'-amino-3'-methoxyflavone (PD98059), had similar off-target effects. We conclude that the levels and hence the signaling strength of [PP](2)-InsP(4) is supervised by cellular adenosine nucleotide balance, signifying a new link between signaling and bioenergetic networks.