The plant plasma membrane proton pump ATPase: a highly regulated P-type ATPase with multiple physiological roles
The plant plasma membrane proton pump ATPase: a highly regulated P-type ATPase with multiple physiological roles
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DOI：
10.1007/s00424-008-0457-x
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发表时间：
2009-01-01
影响因子：
4.5
通讯作者：
Boutry, Marc
中科院分区：
文献类型：
--
作者：
Duby, Geoffrey;Boutry, Marc
在拟南芥和水稻中已经鉴定了大约40种P型ATP酶，其基因组是已知的。似乎没有一个像动物Na+/K+-ATP酶那样交换钠和钾。相反，植物与真菌一起具有质子泵ATP酶（H+-ATP酶），其将ATP水解与质子运输出细胞偶联，并且因此建立跨质膜的电化学梯度，其通过次级转运体使用质子以同向或反向运输消散，如钠在动物细胞中使用的那样。其他功能，如气孔开放，细胞生长，和细胞内pH值的稳态，已被提出。晶体学数据和同源性建模表明，H+-ATP酶具有与其他P-型ATP酶广泛相似的结构，但具有延伸的C-末端区域，其参与酶调节。倒数第二个残基（Thr）的磷酸化和随后调节性14-3-3蛋白的结合导致十二聚体（6个H+-ATP酶和6个14-3-3分子）的形成和酶活化。这种类型的调节是P型ATP酶家族所独有的。然而，最近发现的额外磷酸化残基表明了进一步的调节特征。
Around 40 P-type ATPases have been identified in Arabidopsis and rice, for which the genomes are known. None seems to exchange sodium and potassium, as does the animal Na+/K+-ATPase. Instead, plants, together with fungi, possess a proton pumping ATPase (H+-ATPase), which couples ATP hydrolysis to proton transport out of the cell, and so establishes an electrochemical gradient across the plasma membrane, which is dissipated by secondary transporters using protons in symport or antiport, as sodium is used in animal cells. Additional functions, such as stomata opening, cell growth, and intracellular pH homeostasis, have been proposed. Crystallographic data and homology modeling suggest that the H+-ATPase has a broadly similar structure to the other P-type ATPases but has an extended C-terminal region, which is involved in enzyme regulation. Phosphorylation of the penultimate residue, a Thr, and the subsequent binding of regulatory 14-3-3 proteins result in the formation of a dodecamer (six H+-ATPase and six 14-3-3 molecules) and enzyme activation. This type of regulation is unique to the P-type ATPase family. However, the recent identification of additional phosphorylated residues suggests further regulatory features.