CLC transport proteins in plants.
Zifarelli G., Pusch M.
Nitrate compartmentalization in intracellular organelles has been long recognized as critical for plant physiology but the molecular identity of the proteins involved remained unclear for a long time. In Arabidopsis thaliana, AtClC-a has been recently shown to be a NO(3)(-)/H(+) antiporter critical for nitrate transport into the vacuoles. AtClC-a is a member of the CLC protein family, whose animal and bacterial members, comprising both channels and H(+)-coupled antiporters, have been previously implicated exclusively in Cl(-) transport. Despite the different NO(3)(-) over Cl(-) selectivity of AtClC-a compared to the other CLC antiporters, it has similar transport properties. Other CLC homologues have been cloned in Arabidopsis, tobacco, rice and soybean.