title: [Structure and function of tonoplast Cation/H+ antiporters in plant: a review].
abstract: Cation transporters play important roles in modulating the concentration of intracellular metal ions. The vacuole is an important storage organelle for many ions. Cation (Ca+)/H+ antiporters (CAXs) located at vacuolar membrane are mainly involved in the Ca2+ flux into the vacuole, and appear to be capable of transporting various divalent cations to some degree. Several CAX genes have been isolated and characterized from various plants in recent years. Four domains of plant CAXs have been identified: NRR regulates Ca2+ transport by a mechanism of N-terminal autoinhibition; Ca domain and C domain confer Ca2+ and Mn2+ specificity among CAX transporters, respectively; D domain plays a part in the regulation of cytosolic pH. AtCAXs identified in Arabidopsis thaliana are involved in the growth, development and stress adaption of plant. AtCAX3 is the mainly Ca2+/H+ transporter in response to salt stress; AtCAX2 and AtCAX4 participate in transportation and detoxicification of heavy metal ions (Cd2+, Zn2+, and Mn2+) in cells under heavy metal stress, and impact root/shoot Cd partitioning in plant. These suggest that CAX genes may be useful for nutritional enhancement of plants, and for increasing phytoremediation potential. Here, the classification, structure and function of CAXs in plants are reviewed.
authors.affiliation: School of Chemical and Environmental Engineering, China University of Mining and Technology, Beijng 100083, China.
authors.forename: Yuxiu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Peng
authors.forename: Tuanyao
authors.initials: T
authors.lastname: Chai
authors.forename: Chunling
authors.initials: C
authors.lastname: Zhang
authors.forename: Jinguang
authors.initials: J
authors.lastname: Liu
mesh_terms: D017920:Antiporters / Q000737:chemistry / Q000502:physiology*; D017360:Arabidopsis / Q000737:chemistry; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D027682:Cation Transport Proteins / Q000737:chemistry / Q000502:physiology*; D008565:Membrane Proteins / Q000502:physiology; D019216:Metals, Heavy / Q000378:metabolism; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000502:physiology; D010944:Plants / Q000737:chemistry; D017494:Proton Pumps / Q000737:chemistry / Q000502:physiology*; D014617:Vacuoles / Q000378:metabolism / Q000502:physiology*
chemical_list: D017920:Antiporters; D029681:Arabidopsis Proteins; C506406:CAX3 protein, Arabidopsis; C460090:CAX4 protein, Arabidopsis; D027682:Cation Transport Proteins; D008565:Membrane Proteins; D019216:Metals, Heavy; D010940:Plant Proteins; D017494:Proton Pumps; C027614:calcium-hydrogen antiporters; C077491:tonoplast intrinsic protein, plant; D002118:Calcium