| Abstract: | 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 conserved 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. |
