title: The HAK1 gene of barley is a member of a large gene family and encodes a high-affinity potassium transporter.
abstract: The high-affinity K+ uptake system of plants plays a crucial role in nutrition and has been the subject of extensive kinetic studies. However, major components of this system remain to be identified. We isolated a cDNA from barley roots, HvHAK1, whose translated sequence shows homology to the Escherichia coli Kup and Schwanniomyces occidentalis HAK1 K+ transporters. HvHAK1 conferred high-affinity K+ uptake to a K(+)-uptake-deficient yeast mutant exhibiting the hallmark characteristics of the high-affinity K+ uptake described for barley roots. HvHAK1 also mediated low-affinity Na+ uptake. Another cDNA (HvHAK2) encoding a polypeptide 42% identical to HvHAK1 was also isolated. Analysis of several genomes of Triticeae indicates that HvHAK1 belongs to a multigene family. Translated sequences from bacterial DNAs and Arabidopsis, rice, and possibly human cDNAs show homology to the Kup-HAK1-HvHAK1 family of K+ transporters.
authors.affiliation: Departamento de Biotecnología, Escuela Técnica Superior de Ingenieros Agrónomos, Madrid, Spain.
authors.forename: G E
authors.initials: GE
authors.lastname: Santa-María
authors.forename: F
authors.initials: F
authors.lastname: Rubio
authors.forename: J
authors.initials: J
authors.lastname: Dubcovsky
authors.forename: A
authors.initials: A
authors.lastname: Rodríguez-Navarro
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D027682:Cation Transport Proteins; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D017343:Genes, Plant; D001467:Hordeum / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D005810:Multigene Family; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011188:Potassium / Q000378:metabolism*; D004718:Saccharomycetales / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: D002352:Carrier Proteins; D027682:Cation Transport Proteins; D017931:DNA Primers; D018076:DNA, Complementary; C110543:HAK1 protein, plant; C110544:HAK2 protein, Hordeum vulgare; D010940:Plant Proteins; D011188:Potassium