Guard Cell Inward K+ Channel Activity inArabidopsis Involves Expression of the Twin Channel Subunits KAT1 and KAT2

作者：Guillaume Pilot, Benoı̂t Lacombe, Frédéric Gaymard, Isabelle Chérel, Jossia Boucherez, Jean‐Baptiste Thibaud, Hervé Sentenac · 发表于：Journal of Biological Chemistry · 年份：2001 · DOI：10.1074/jbc.m007303200 · 被引用次数：253 · 研究领域：Plant Stress Responses and Tolerance、Plant Molecular Biology Research、Plant Reproductive Biology

Stomatal opening, which controls gas exchanges between plants and the atmosphere, results from an increase in turgor of the two guard cells that surround the pore of the stoma. KAT1 was the only inward K(+) channel shown to be expressed in Arabidopsis guard cells, where it was proposed to mediate a K(+) influx that enables stomatal opening. We report that another Arabidopsis K(+) channel, KAT2, is expressed in guard cells. More than KAT1, KAT2 displays functional features resembling those of native inward K(+) channels in guard cells. Coexpression in Xenopus oocytes and two-hybrid experiments indicated that KAT1 and KAT2 can form heteromultimeric channels. The data indicate that KAT2 plays a crucial role in the stomatal opening machinery.