Water is an important component in plant cells with plant aquaporin being the major protein for water transport in and between plant cells. As a subfamily of plant aquaporins, the plasma membrane intrinsic proteins (PIPs) located in the plasma membrane are classic, high water, selective channel proteins. This paper focuses on recent advances in the molecular biology of PIPs concerning structural characteristics, biological function, and a regulation mechanism. PIPs possess two highly conserved domains; GGGANXXXXGY and TGI/TNPARSL/FGAAI/VI/VFWF/YN. PIPs can also be divided into two phylogenetic subgroups named PIP1 and PIP2. PIP1 possesses longer N terminal sequences and shorter C terminal sequences than PIP2 with con served amino acid sequences respectively. Studies of transgenic plants and expression in Xenopus oocytes cells indicate that PIPs not only may facilitate transport of water and small neutral solutes like CO2 and glycerin, but they also possess many physiological functions. The functions of plant aquaporins are regulated by many factors including post-translational modification, heteromerization, pH value, and divalent cations. These results indicated that PIPs act as a pivotal role in water and small neutral solutes transport in plants. [Ch, 1 tab. 51 ref.]%水是植物细胞的重要组成成分,植物水通道蛋白是细胞间和细胞内水分快速运输的主要通道,作为植物水通道蛋白的一个亚类,质膜内在蛋白PIPs定位于原生质膜,为典型的高水分选择性通道蛋白.主要介绍了PIPs的结构特征、生物学功能及其调控机制.高等植物PIPs存在2个高度保守的区域:GGGANXXXXGY和TGI/TNPARSL/FGAAI/VI/VFWF/YN.PIPs分为PIP1和PIP2亚类,PIP1比PIP2具较长的N-端和较短的C-端,并且具有各自的保守氨基酸.通过转基因和非洲爪蟾卵Xenopus oocytes母细胞异源表达研究表明PIPs不仅是水和二氧化碳、甘油等中性小分子选择性通道蛋白,同时还具有许多生理功能,是一类多功能蛋白.蛋白翻译后修饰、异聚化、pH值、二价阳离子等都能调控PIPs的运输功能.
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