Australian Research Council (ARC) Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine, University of Adelaide, Glen Osmond, South Australia 5064, Australia; email:
ARC Centre of Excellence for Translational Photosynthesis, Division of Plant Sciences, Research School of Biology, Australian National University, Acton, Australian Capital Territory 0200, Australia; email:
Annu Rev Plant Biol. 2021 Jun 17;72:703-736. doi: 10.1146/annurev-arplant-081720-013608. Epub 2021 Feb 12.
Aquaporins function as water and neutral solute channels, signaling hubs, disease virulence factors, and metabolon components. We consider plant aquaporins that transport ions compared to some animal counterparts. These are candidates for important, as yet unidentified, cation and anion channels in plasma, tonoplast, and symbiotic membranes. For those individual isoforms that transport ions, water, and gases, the permeability spans 12 orders of magnitude. This requires tight regulation of selectivity via protein interactions and posttranslational modifications. A phosphorylation-dependent switch between ion and water permeation in AtPIP2;1 might be explained by coupling between the gates of the four monomer water channels and the central pore of the tetramer. We consider the potential for coupling between ion and water fluxes that could form the basis of an electroosmotic transducer. A grand challenge in understanding the roles of ion transporting aquaporins is their multifunctional modes that are dependent on location, stress, time, and development.
水通道蛋白作为水和中性溶质通道、信号枢纽、疾病毒力因子和代谢物组件发挥作用。我们将比较植物水通道蛋白与一些动物水通道蛋白的离子运输功能。这些水通道蛋白可能是质膜、液泡膜和共生膜中尚未确定的重要阳离子和阴离子通道的候选蛋白。对于那些既能运输离子又能运输水和气体的单一水通道蛋白，其通透性跨越 12 个数量级。这需要通过蛋白质相互作用和翻译后修饰来严格调节选择性。AtPIP2;1 中离子和水渗透的磷酸化依赖性开关可能是通过四个单体水通道的门和四聚体中央孔之间的偶联来解释的。我们考虑了离子和水通量之间可能形成电渗流传感器基础的偶联的可能性。理解离子转运水通道蛋白作用的一个巨大挑战是它们的多功能模式，这些模式取决于位置、胁迫、时间和发育。
