Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Campus Talca, Universidad de Talca, 1 Poniente No. 1141, Casilla 721, 3460000 Talca, Chile.
Plant Biology Section, School of Integrative Plant Science, Cornell University, Ithaca, NY 14853, USA.
Int J Mol Sci. 2021 Feb 14;22(4):1892. doi: 10.3390/ijms22041892.
HKT channels are a plant protein family involved in sodium (Na) and potassium (K) uptake and Na-K homeostasis. Some HKTs underlie salt tolerance responses in plants, while others provide a mechanism to cope with short-term K shortage by allowing increased Na uptake under K starvation conditions. HKT channels present a functionally versatile family divided into two classes, mainly based on a sequence polymorphism found in the sequences underlying the selectivity filter of the first pore loop. Physiologically, most class I members function as sodium uniporters, and class II members as Na/K symporters. Nevertheless, even within these two classes, there is a high functional diversity that, to date, cannot be explained at the molecular level. The high complexity is also reflected at the regulatory level. HKT expression is modulated at the level of transcription, translation, and functionality of the protein. Here, we summarize and discuss the structure and conservation of the HKT channel family from algae to angiosperms. We also outline the latest findings on gene expression and the regulation of HKT channels.
HKT 通道是一种植物蛋白家族，参与钠（Na）和钾（K）的摄取以及 Na-K 平衡。一些 HKT 参与植物的耐盐响应，而另一些则通过在 K 饥饿条件下允许增加 Na 摄取来提供应对短期 K 短缺的机制。HKT 通道是一个功能多样的家族，分为两类，主要基于第一个孔环选择性过滤器下序列中的序列多态性。从生理上讲，大多数 I 类成员作为钠离子单向转运体起作用，而 II 类成员作为 Na/K 协同转运体起作用。然而，即使在这两类中，也存在很高的功能多样性，迄今为止，这在分子水平上还无法解释。这种高复杂性也反映在调节水平上。HKT 的表达在转录、翻译和蛋白质功能水平上受到调节。在这里，我们总结和讨论了从藻类到被子植物的 HKT 通道家族的结构和保守性。我们还概述了关于 HKT 通道基因表达和调节的最新发现。
