Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya, Japan.
Plant Signal Behav. 2012 Aug;7(8):979-82. doi: 10.4161/psb.20936. Epub 2012 Jul 27.
The plasma membrane H (+) -ATPase provides the driving force for solute transport via an electrochemical gradient of H (+) across the plasma membrane, and regulates pH homeostasis and membrane potential in plant cells. However, the plasma membrane H (+) -ATPase in non-vascular plant bryophyte is largely unknown. Here, we show that the moss Physcomitrella patens, which is known as a model bryophyte, expresses both the penultimate Thr-containing H (+) -ATPase (pT H (+) -ATPase) and non-pT H (+) -ATPase as in the green algae, and that pT H (+) -ATPase is regulated by phosphorylation of its penultimate Thr. A search in the P. patens genome database revealed seven H (+) -ATPase genes, designated PpHA (Physcomitrella patens H (+) -ATPase). Six isoforms are the pT H (+) -ATPase; a remaining isoform is non-pT H (+) -ATPase. An apparent 95-kD protein was recognized by anti-H (+) -ATPase antibodies against an isoform of Arabidopsis thaliana and was phosphorylated on the penultimate Thr in response to a fungal toxin fusicoccin and light in protonemata, indicating that the 95-kD protein contains pT H (+) -ATPase. Furthermore, we could not detect the pT H (+) -ATPase in the charophyte alga Chara braunii, which is the closest relative of the land plants, by immunological methods. These results strongly suggest the pT H (+) -ATPase most likely appeared for the first time in bryophyte.
质膜 H (+) -ATP 酶通过跨质膜的 H (+) 电化学梯度为溶质转运提供驱动力，并调节植物细胞的 pH 稳态和膜电位。然而，在非维管植物苔藓中，质膜 H (+) -ATP 酶在很大程度上是未知的。在这里，我们表明，众所周知的苔藓模式生物Physcomitrella patens 既表达了最后一个 Thr 残基的 H (+) -ATP 酶（pT H (+) -ATP 酶），也表达了绿藻中的非 pT H (+) -ATP 酶，并且 pT H (+) -ATP 酶受到其最后一个 Thr 残基的磷酸化调节。在 P. patens 基因组数据库中的搜索显示，有七个 H (+) -ATP 酶基因，被命名为 PpHA（Physcomitrella patens H (+) -ATP 酶）。六个同工型是 pT H (+) -ATP 酶；剩下的一个同工型是非 pT H (+) -ATP 酶。抗拟南芥同工型的抗 H (+) -ATP 酶抗体识别出一种表观 95-kD 蛋白，并在真菌毒素 fusicoccin 和光刺激原丝体时在最后一个 Thr 残基上发生磷酸化，表明 95-kD 蛋白含有 pT H (+) -ATP 酶。此外，我们无法通过免疫方法在与陆地植物关系最密切的轮藻目藻类 Chara braunii 中检测到 pT H (+) -ATP 酶。这些结果强烈表明，pT H (+) -ATP 酶很可能首次出现在苔藓植物中。
