title: A plant homolog of animal chloride intracellular channels (CLICs) generates an ion conductance in heterologous systems.
abstract: The genome of Arabidopsis thaliana contains unusual members of the glutathione S-transferase (GST) superfamily with a cysteine in place of a serine at the active site. Four of these genes (at-dhar 1-4) have an appreciable homology to intracellular Cl- channels (CLICs) from vertebrates and invertebrates. Transient expression of AtDHAR1 as wild type protein or as a chimera with GFP in mammalian HEK293 or Chinese hamster ovary cells generated a distinct inward rectifying conductance with a characteristic biphasic kinetics but no apparent ion selectivity. Analysis of the subcellular localization of AtDHRA1::GFP showed that the bulk of the protein was located as soluble form in the cytoplasm; however, an appreciable fraction of it could also be found in association with the non-soluble microsomal fraction. These data suggest that plant members of the GST superfamily have similar to those from animals multiple functions. The increase of ion conductance by AtDHAR1 is better explained by a CLIC-like channel activity than by a modification of endogenous channel proteins.
authors.affiliation: Institute of Botany, Darmstadt University of Technology, D-64287 Darmstadt, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Elter
authors.forename: Andreas
authors.initials: A
authors.lastname: Hartel
authors.forename: Christian
authors.initials: C
authors.lastname: Sieben
authors.forename: Brigitte
authors.initials: B
authors.lastname: Hertel
authors.forename: Elke
authors.initials: E
authors.lastname: Fischer-Schliebs
authors.forename: Ulrich
authors.initials: U
authors.lastname: Lüttge
authors.forename: Anna
authors.initials: A
authors.lastname: Moroni
authors.forename: Gerhard
authors.initials: G
authors.lastname: Thiel
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000235:genetics*; D029681:Arabidopsis Proteins / Q000737:chemistry* / Q000235:genetics / Q000502:physiology; D016466:CHO Cells; D018118:Chloride Channels / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D005260:Female; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D006801:Humans; D007477:Ions / Q000378:metabolism*; D008969:Molecular Sequence Data; D010053:Ovary / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
chemical_list: D029681:Arabidopsis Proteins; D018118:Chloride Channels; D007477:Ions; C519170:DHAR1 protein, Arabidopsis; D005982:Glutathione Transferase