Frachisse J M, Colcombet J, Guern J, Barbier-Brygoo H
Institut des Sciences Végétales, CNRS, UPR 40, Avenue de la Terrasse, 91198 Gif sur Yvette Cedex, France.
Plant J. 2000 Feb;21(4):361-71. doi: 10.1046/j.1365-313x.2000.00689.x.
We have characterized a new anionic current in Arabidopsis hypocotyl cells. This current, activated by membrane depolarization, has slow activation and deactivation kinetics in the 10 sec range. It presents many distinct properties from the rapid-type anion current already described on the same membrane. The slow-type channel is highly permeable to nitrate with a PNO3-/PCl- close to 20, but totally impermeable to sulphate. Activation of the channel requires cytosolic ATP and the slow current is partially inhibited by staurosporin, suggesting that channel regulation involves protein phosphorylation. The slow anion channel displays a unique pharmacological profile different from that of the rapid channel: the slow channel is inhibited by DIDS (4, 4'-diisothiocyanatostilbene-2,2'-disulfonic acid) with an IC50 of 26 microM. The slow and rapid anion channels are probably dedicated to specific functions: the first is able to mediate sustained anion efflux, while the second is a good candidate to be involved in fast electrical signalling.
我们已对拟南芥下胚轴细胞中的一种新型阴离子电流进行了特性描述。这种电流由膜去极化激活，在10秒范围内具有缓慢的激活和失活动力学。它与同一膜上已描述的快速型阴离子电流具有许多不同特性。慢型通道对硝酸盐具有高度通透性，PNO3-/PCl-接近20，但对硫酸盐完全不通透。通道的激活需要胞质ATP，并且慢电流部分受星形孢菌素抑制，这表明通道调节涉及蛋白质磷酸化。慢阴离子通道表现出与快速通道不同的独特药理学特征：慢通道被DIDS（4,4'-二异硫氰基芪-2,2'-二磺酸）抑制，IC50为26 microM。慢阴离子通道和快速阴离子通道可能具有特定功能：前者能够介导持续的阴离子外流，而后者很可能参与快速电信号传导。
