CAX1, an H+/Ca2+ antiporter from Arabidopsis

Proc Natl Acad Sci U S A. 1996 Aug 6;93(16):8782-6. doi: 10.1073/pnas.93.16.8782.


Reestablishment of the resting state after stimulus-coupled elevations of cytosolic-free Ca2+ requires the rapid removal of Ca2+ from the cytosol of plant cells. Here we describe the isolation of two genes, CAX1 and CAX2, from Arabidopsis thaliana that suppress a mutant of Saccharomyces cerevisiae that has a defect in vacuolar Ca2+ accumulation. Both genes encode polypeptides showing sequence similarities to microbial H+/Ca2+ antiporters. Experiments on vacuolar membrane-enriched vesicles isolated from yeast expressing CAX1 or CAX2 demonstrate that these genes encode high efficiency and low efficiency H+/Ca2+ exchangers, respectively. The properties of the CAX1 gene product indicate that it is the high capacity transporter responsible for maintaining low cytosolic-free Ca2+ concentrations in plant cells by catalyzing pH gradient-energized vacuolar Ca2+ accumulation.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Antiporters / genetics*
  • Arabidopsis / genetics*
  • Base Sequence
  • Biological Transport
  • Calcium / metabolism*
  • Calcium-Binding Proteins / genetics*
  • Cation Transport Proteins*
  • Cell-Free System
  • DNA Primers / chemistry
  • DNA, Complementary / genetics
  • Genes, Plant*
  • Hydrogen-Ion Concentration
  • Molecular Sequence Data
  • Plant Proteins / genetics*
  • Recombinant Proteins
  • Saccharomyces cerevisiae
  • Sequence Homology, Amino Acid
  • Solubility
  • Transformation, Genetic
  • Vacuoles / chemistry
  • Vacuoles / metabolism


  • Antiporters
  • Calcium-Binding Proteins
  • Cation Transport Proteins
  • DNA Primers
  • DNA, Complementary
  • Plant Proteins
  • Recombinant Proteins
  • calcium-hydrogen antiporters
  • Calcium

Associated data

  • GENBANK/D15647
  • GENBANK/P31801
  • GENBANK/U36603
  • GENBANK/U57411
  • GENBANK/U57412