Sodium or potassium efflux ATPase a fungal, bryophyte, and protozoal ATPase

Biochim Biophys Acta. 2010 Oct;1798(10):1841-53. doi: 10.1016/j.bbamem.2010.07.009. Epub 2010 Jul 19.


The K(+) and Na(+) concentrations in living cells are strictly regulated at almost constant concentrations, high for K(+) and low for Na(+). Because these concentrations correspond to influx-efflux steady states, K(+) and Na(+) effluxes and the transporters involved play a central role in the physiology of cells, especially in environments with high Na(+) concentrations where a high Na(+) influx may be the rule. In eukaryotic cells two P-type ATPases are crucial in these homeostatic processes, the Na,K-ATPase of animal cells and the H(+)-ATPase of fungi and plants. In fungi, a third P-type ATPase, the ENA ATPase, was discovered nineteen years ago. Although for many years it was considered to be exclusively a fungal enzyme, it is now known to be present in bryophytes and protozoa. Structurally, the ENA (from exitus natru: exit of sodium) ATPase is very similar to the sarco/endoplasmic reticulum Ca(2+) (SERCA) ATPase, and it probably exchanges Na(+) (or K(+)) for H(+). The same exchange is mediated by Na(+) (or K(+))/H(+) antiporters. However, in eukaryotic cells these antiporters are electroneutral and their function depends on a DeltapH across the plasma membrane. Therefore, the current notion is that the ENA ATPase is necessary at high external pH values, where the antiporters cannot mediate uphill Na(+) efflux. This occurs in some fungal environments and at some points of protozoa parasitic cycles, which makes the ENA ATPase a possible target for controlling fungal and protozoan parasites. Another technological application of the ENA ATPase is the improvement of salt tolerance in flowering plants.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism
  • Molecular Sequence Data
  • Phylogeny*
  • Plant Proteins / genetics
  • Plant Proteins / metabolism
  • Potassium / metabolism*
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Sodium / metabolism*
  • Sodium-Potassium-Exchanging ATPase / classification
  • Sodium-Potassium-Exchanging ATPase / genetics
  • Sodium-Potassium-Exchanging ATPase / metabolism*


  • Fungal Proteins
  • Plant Proteins
  • Protozoan Proteins
  • Sodium
  • Sodium-Potassium-Exchanging ATPase
  • Potassium