Hyperacidification of Vacuoles by the Combined Action of Two Different P-ATPases in the Tonoplast Determines Flower Color
Hyperacidification of Vacuoles by the Combined Action of Two Different P-ATPases in the Tonoplast Determines Flower Color
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DOI：
10.1016/j.celrep.2013.12.009
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发表时间：
2014-01-01
期刊：
影响因子：
8.8
通讯作者：
Quattrocchio, Francesca M.
中科院分区：
文献类型：
--
作者：
Faraco, Marianna;Spelt, Cornelis;Quattrocchio, Francesca M.
内膜区室的酸化对于各种化合物的酶活性、分选、运输和跨膜运输是必不可少的。由于V-ATP酶和/或焦磷酸酶质子泵的作用，大多数植物细胞中的多酚是弱酸性的，但在特定细胞中通过尚不清楚的机制被过度酸化。在这里，我们表明，蓝色花瓣颜色的矮牵牛ph突变体是由于未能过酸化液泡。我们报告说，PH 1编码的P-3B-ATPase，迄今已知的Mg 2+转运蛋白在细菌中，驻留在液泡膜（液泡膜）。体内核磁共振和遗传数据表明，PH 1是必需的，并且与液泡膜H+ P-3A-ATPase PH 5一起足以使液泡过酸化。PH 1本身没有H+转运活性，但可以与PH 5发生物理相互作用，促进PH 5的H+转运活性。因此，花瓣中的液泡以及可能的其他组织中的液泡的过度酸化依赖于异聚体P-ATP酶泵。
The acidification of endomembrane compartments is essential for enzyme activities, sorting, trafficking, and trans-membrane transport of various compounds. Vacuoles are mildly acidic inmost plant cells because of the action of V-ATPase and/or pyrophosphatase proton pumps but are hyperacidified in specific cells by mechanisms that remained unclear. Here, we show that the blue petal color of petunia ph mutants is due to a failure to hyperacidify vacuoles. We report that PH1 encodes a P-3B-ATPase, hitherto known as Mg2+ transporters in bacteria only, that resides in the vacuolar membrane (tonoplast). In vivo nuclear magnetic resonance and genetic data show that PH1 is required and, together with the tonoplast H+ P-3A-ATPase PH5, sufficient to hyperacidify vacuoles. PH1 has no H+ transport activity on its own but can physically interact with PH5 and boost PH5 H+ transport activity. Hence, the hyperacidification of vacuoles in petals, and possibly other tissues, relies on a heteromeric P-ATPase pump.