Peptidyl-prolyl cis-trans isomerase ROF2 modulates intracellular pH homeostasis in Arabidopsis
Peptidyl-prolyl cis-trans isomerase ROF2 modulates intracellular pH homeostasis in Arabidopsis
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DOI：
10.1111/j.1365-313x.2012.04921.x
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发表时间：
2012-05-01
期刊：
影响因子：
7.2
通讯作者：
Serrano, Ramon
中科院分区：
文献类型：
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作者：
Bissoli, Gaetano;Ninoles, Regina;Serrano, Ramon
细胞内pH必须保持接近中性才能与细胞功能相容，但pH稳态的机制和对细胞内酸化的反应大多是未知的。在拟南芥（Arabidopsis thaliana）中，我们发现在正常外部pH下由弱有机酸产生的细胞内酸胁迫诱导了几个伴侣基因的表达，包括编码fk506结合蛋白类肽酰脯氨酸顺式反式异构酶的ROF2。ROF2功能丧失，尤其是ROF2及其密切相关基因ROF1的双突变，会导致酸敏感。过度表达ROF2通过增加细胞中质子的挤压，赋予细胞内酸化的耐受性。质膜质子泵（H+- atp酶）的激活是间接的：ROF2的过度表达激活K+摄取，引起质膜的去极化，从而激活电致H+泵。过表达ROF2的植物的去极化解释了它们对有毒阳离子（如锂、去亚精子胺和湿霉素B）的耐受性，这些阳离子的吸收是由膜电位驱动的。由于ROF2诱导和细胞内酸化是许多胁迫的共同后果，这种pH稳态机制可能对胁迫耐受性具有普遍重要性。
Intracellular pH must be kept close to neutrality to be compatible with cellular functions, but the mechanisms of pH homeostasis and the responses to intracellular acidification are mostly unknown. In the plant Arabidopsis thaliana, we found that intracellular acid stress generated by weak organic acids at normal external pH induces expression of several chaperone genes, including ROF2, which encodes a peptidyl-prolyl cis-trans isomerase of the FK506-binding protein class. Loss of function of ROF2, and especially double mutation of ROF2 and the closely related gene ROF1, results in acid sensitivity. Over-expression of ROF2 confers tolerance to intracellular acidification by increasing proton extrusion from cells. The activation of the plasma membrane proton pump (H+-ATPase) is indirect: over-expression of ROF2 activates K+ uptake, causing depolarization of the plasma membrane, which activates the electrogenic H+ pump. The depolarization of ROF2 over-expressing plants explains their tolerance to toxic cations such as lithium, norspermidine and hygromycin B, whose uptake is driven by the membrane potential. As ROF2 induction and intracellular acidification are common consequences of many stresses, this mechanism of pH homeostasis may be of general importance for stress tolerance.