Kaldenhoff Ralf, Bertl Adam, Otto Beate, Moshelion Menachem, Uehlein Norbert
Institute of Botany, Applied Plant Sciences, Darmstadt University of Technology, Darmstadt, Germany.
Methods Enzymol. 2007;428:505-31. doi: 10.1016/S0076-6879(07)28028-0.
Plants have been reported to contain a large set of aquaporins (38 for Arabidopsis), which has been divided into four subfamilies on the basis of similarities in their amino acid sequences. They belong to the large superfamily of major intrinsic proteins (MIP), which was the basis for the nomenclature PIP, TIP, and NIP, also indicating the subcellular localization plasma membrane, tonoplast, and nodule of the respective founding member. The fourth subfamily of small and basic intrinsic proteins is not well characterized so far. The increasing number of reports dealing with various aspects of plant aquaporins is starting to advance our understanding of aquaporin biology in plants. Fundamental questions include: what is the basic function of the different plant aquaporins, what is their primary substrate, and what is the consequence of function/malfunction of a particular aquaporin for the overall function of the plant? Biochemical and biophysical techniques can be employed to get information on the basic functional characteristics of plant aquaporins. An impressive set of techniques has been used to study aquaporin function on molecular, subcellular, and cellular levels in plants, as well as in heterologous expression systems. The physiological role of aquaporins in plants is much less well understood, but reports unraveling the physiological role of aquaporins, mainly employing genetic techniques and functional measurement on the whole plant level, are emerging. The goal of this chapter is to give an overview on the applied methods, together with some exemplary findings.
据报道，植物含有大量水通道蛋白（拟南芥中有38种），根据其氨基酸序列的相似性可分为四个亚家族。它们属于主要内在蛋白（MIP）的大型超家族，这也是命名PIP、TIP和NIP的基础，同时也表明了各自创始成员的亚细胞定位——质膜、液泡膜和根瘤。到目前为止，小型碱性内在蛋白的第四个亚家族还没有得到很好的表征。越来越多关于植物水通道蛋白各个方面的报道开始增进我们对植物水通道蛋白生物学的理解。基本问题包括：不同植物水通道蛋白的基本功能是什么，它们的主要底物是什么，特定水通道蛋白的功能/功能失调对植物整体功能有什么影响？可以采用生化和生物物理技术来获取有关植物水通道蛋白基本功能特性的信息。已经使用了一系列令人印象深刻的技术来研究植物以及异源表达系统中分子、亚细胞和细胞水平上的水通道蛋白功能。水通道蛋白在植物中的生理作用了解得还很少，但主要采用遗传技术和全植物水平功能测量来揭示水通道蛋白生理作用的报道正在出现。本章的目的是对所应用的方法以及一些示例性发现进行概述。
