Plant cation/H+ exchangers (CAXs): biological functions and genetic manipulations

Plant Biol (Stuttg). 2011 Jul;13(4):561-9. doi: 10.1111/j.1438-8677.2011.00466.x. Epub 2011 May 12.


Inorganic cations play decisive roles in many cellular and physiological processes and are essential components of plant nutrition. Therefore, the uptake of cations and their redistribution must be precisely controlled. Vacuolar antiporters are important elements in mediating the intracellular sequestration of these cations. These antiporters are energized by the proton gradient across the vacuolar membrane and allow the rapid transport of cations into the vacuole. CAXs (for CAtion eXchanger) are members of a multigene family and appear to predominately reside on vacuoles. Defining CAX regulation and substrate specificity have been aided by utilising yeast as an experimental tool. Studies in plants suggest CAXs regulate apoplastic Ca(2+) levels in order to optimise cell wall expansion, photosynthesis, transpiration and plant productivity. CAX studies provide the basis for making designer transporters that have been used to develop nutrient enhanced crops and plants for remediating toxic soils.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Review

MeSH terms

  • Antiporters / metabolism*
  • Calcium / metabolism
  • Cation Transport Proteins / genetics
  • Cation Transport Proteins / metabolism*
  • Cations / metabolism*
  • Gene Expression Regulation, Plant*
  • Intracellular Membranes / metabolism*
  • Plants / genetics
  • Plants / metabolism*
  • Proton Pumps / metabolism
  • Vacuoles / metabolism*


  • Antiporters
  • Cation Transport Proteins
  • Cations
  • Proton Pumps
  • Calcium