Structure and transport mechanism of a high-affinity potassium uptake transporter from higher plants

Nature. 1994 Aug 25;370(6491):655-8. doi: 10.1038/370655a0.


Potassium is the most abundant cation in higher plants and is crucial for plant nutrition, growth, tropisms, enzyme homeostasis and osmoregulation. K+ accumulation can be rate-limiting for agricultural production. K+ uptake from soils into roots is largely mediated by high-affinity K+ uptake (Km approximately 10-40 microM) (refs 1, 2, 5-7). But although K+ channels allow low-affinity K+ uptake, both the transport mechanism and structure of the high-affinity K+ nutrition pathway remain unknown. Here we use expression cloning to isolate a complementary DNA encoding a membrane protein (HKT1) from wheat roots which confers the ability to take up K+. The substrate affinity, saturation and cation selectivity of HKT1 correspond to hallmark properties of classical high-affinity K+ uptake in plants. The transport mechanism of HKT1 uses K(+)-H+ co-uptake. Expression of HKT1 is localized to specific root and leaf regions which represent primary sites for K+ uptake in plants. HKT1 is important for plant nutrition and could possibly contribute to environmental alkali metal toxicities.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Biological Transport
  • Carrier Proteins / genetics
  • Carrier Proteins / metabolism*
  • Cation Transport Proteins*
  • Cells, Cultured
  • Cloning, Molecular
  • DNA
  • Gene Expression
  • Genes, Plant
  • Membrane Potentials
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Molecular Sequence Data
  • Oocytes
  • Plant Proteins / genetics
  • Plant Proteins / metabolism*
  • Potassium / metabolism*
  • Saccharomyces cerevisiae
  • Symporters*
  • Triticum / genetics
  • Triticum / metabolism*
  • Xenopus


  • Carrier Proteins
  • Cation Transport Proteins
  • HKT1 protein, plant
  • Membrane Proteins
  • Plant Proteins
  • Symporters
  • DNA
  • Potassium

Associated data

  • GENBANK/U16709