A Thylakoid-Located Two-Pore K+ Channel Controls Photosynthetic Light Utilization in Plants
A Thylakoid-Located Two-Pore K+ Channel Controls Photosynthetic Light Utilization in Plants
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DOI：
10.1126/science.1242113
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发表时间：
2013-10-04
期刊：
影响因子：
56.9
通讯作者：
Szabo, Ildiko
中科院分区：
文献类型：
--
作者：
Carraretto, Luca;Formentin, Elide;Szabo, Ildiko
叶绿体类囊体膜上光诱导的质子动力（pmf）的大小受环境刺激的调节。在这里，我们描述了类囊体膜的一个组成部分，双孔钾（K+）通道TPK3，它通过离子平衡调节pmf的组成。重组TPK3具有对Ca~（2+）和H~+敏感的钾通道活性。在拟南芥中，该通道存在于类囊体基质层中。沉默TPK3基因的拟南芥植株生长减少，类囊体膜结构改变。这种表型反映了产生正常pmf的能力受损，这导致CO2同化减少和过量吸收光的非光化学耗散不足。因此，TPK3通道管理将光化学能转化为生理功能所需的pmf。
The size of the light-induced proton motive force (pmf) across the thylakoid membrane of chloroplasts is regulated in response to environmental stimuli. Here, we describe a component of the thylakoid membrane, the two-pore potassium (K+) channel TPK3, which modulates the composition of the pmf through ion counterbalancing. Recombinant TPK3 exhibited potassium-selective channel activity sensitive to Ca2+ and H+. In Arabidopsis plants, the channel is found in the thylakoid stromal lamellae. Arabidopsis plants silenced for the TPK3 gene display reduced growth and altered thylakoid membrane organization. This phenotype reflects an impaired capacity to generate a normal pmf, which results in reduced CO2 assimilation and deficient nonphotochemical dissipation of excess absorbed light. Thus, the TPK3 channel manages the pmf necessary to convert photochemical energy into physiological functions.