Functional dependence on calcineurin by variants of the Saccharomyces cerevisiae vacuolar Ca2+/H+ exchanger Vcx1p

Mol Microbiol. 2004 Nov;54(4):1104-16. doi: 10.1111/j.1365-2958.2004.04332.x.


The Ca(2+)-dependent protein phosphatase calcineurin is an important regulator of ion transporters from many organisms, including the Saccharomyces cerevisiae vacuolar Ca(2+)/H(+) exchanger Vcx1p. In yeast and plants, cation/H(+) exchangers are important in shaping cytosolic Ca(2+) levels involved in signal transduction and providing tolerance to potentially toxic concentrations of cations such as Ca(2+), Mn(2+) and Cd(2+). Previous genetic evidence suggested Vcx1p is negatively regulated by calcineurin. By utilizing direct transport measurements into vacuolar membrane vesicles, we demonstrate that Vcx1p is a low-affinity Ca(2+) transporter and may also function in Cd(2+) transport, but cannot transport Mn(2+). Furthermore, direct Ca(2+) transport by Vcx1p is calcineurin sensitive. Using a yeast growth assay, a mutant allele of VCX1 (VCX1-S204A/L208P), termed VCX1-M1, was previously found to confer strong Mn(2+) tolerance. Here we demonstrate that this Mn(2+) tolerance is independent of the Ca(2+)/Mn(2+)-ATPase Pmr1p and results from Mn(2+)-specific vacuolar transport activity of Vcx1-M1p. This Mn(2+) transport by Vcx1-M1p is calcineurin dependent, although the localization of Vcx1-M1p to the vacuole appears to be calcineurin independent. Additionally, we demonstrate that mutation of L208P alone is enough to confer calcineurin-dependent Mn(2+) tolerance. This study demonstrates that calcineurin can positively regulate the transport of cations by VCX1-M1p.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antiporters / genetics
  • Antiporters / metabolism*
  • Biological Transport / physiology
  • Cadmium / metabolism
  • Calcineurin / metabolism*
  • Calcium / metabolism
  • Calcium-Transporting ATPases / metabolism
  • Manganese / metabolism
  • Molecular Chaperones / metabolism
  • Point Mutation
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Vacuoles / metabolism


  • Antiporters
  • Molecular Chaperones
  • Protein Isoforms
  • SSC1 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • VCX1 protein, S cerevisiae
  • Cadmium
  • Manganese
  • Calcineurin
  • Calcium-Transporting ATPases
  • Calcium