Dirigent domain-containing protein is part of the machinery required for formation of the lignin-based Casparian strip in the root
Dirigent domain-containing protein is part of the machinery required for formation of the lignin-based Casparian strip in the root
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DOI：
10.1073/pnas.1308412110
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发表时间：
2013-08-27
影响因子：
11.1
通讯作者：
Salt, David E.
中科院分区：
文献类型：
--
作者：
Hosmani, Prashant S.;Kamiya, Takehiro;Salt, David E.
内皮层作为植物根的“第二层皮肤”，为水和溶质选择性进入维管系统提供必要的细胞控制。为了实现这种控制，凯氏带跨越相邻内胚层细胞的细胞壁以形成紧密连接，其阻断细胞外扩散穿过内胚层。这种连接由木质素组成，木质素通过NADPH氧化酶和过氧化物酶的作用通过单木质素的氧化偶联而聚合。凯氏带结构域蛋白（CASP）通过在凯氏带形成的位点处的质膜中形成蛋白质支架来正确地定位这种生物合成机制。在这里，我们表明，含有蛋白质，增强木栓蛋白1（ESB1），是这种机制的一部分，在正确形成凯氏带中发挥着至关重要的作用。ESB1以CASP依赖的方式定位于凯氏带，并且在不存在ESB1的情况下，形成无序和有缺陷的凯氏带。此外，ESB1的缺失破坏了CASP1蛋白在凯氏条带结构域的定位，表明在形成凯氏条带结构域时ESB1和CASPs两者的相互需要
The endodermis acts as a "second skin" in plant roots by providing the cellular control necessary for the selective entry of water and solutes into the vascular system. To enable such control, Casparian strips span the cell wall of adjacent endodermal cells to form a tight junction that blocks extracellular diffusion across the endodermis. This junction is composed of lignin that is polymerized by oxidative coupling of monolignols through the action of a NADPH oxidase and peroxidases. Casparian strip domain proteins (CASPs) correctly position this biosynthetic machinery by forming a protein scaffold in the plasma membrane at the site where the Casparian strip forms. Here, we show that the dirigent-domain containing protein, enhanced suberin1 (ESB1), is part of this machinery, playing an essential role in the correct formation of Casparian strips. ESB1 is localized to Casparian strips in a CASP-dependent manner, and in the absence of ESB1, disordered and defective Casparian strips are formed. In addition, loss of ESB1 disrupts the localization of the CASP1 protein at the casparian strip domain, suggesting a reciprocal requirement for both ESB1 and CASPs in forming the casparian strip domain