期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2002
卷号：99
期号：6
页码：4079-4084
DOI：10.1073/pnas.052677799
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Ion channels in roots allow the plant to gain access to nutrients. The composition of the individual ion channels and the functional contribution of different -subunits is largely unknown. Focusing on K+-selective ion channels, we have characterized AtKC1, a new -subunit from the Arabidopsis shaker-like ion channel family. Promoter-{beta}-glucuronidase (GUS) studies identified AtKC1 expression predominantly in root hairs and root endodermis. Specific antibodies recognized AtKC1 at the plasma membrane. To analyze further the abundance and the functional contribution of the different K+ channels -subunits in root cells, we performed real-time reverse transcription-PCR and patch-clamp experiments on isolated root hair protoplasts. Studying all shaker-like ion channel -subunits, we only found the K+ inward rectifier AtKC1 and AKT1 and the K+ outward rectifier GORK to be expressed in this cell type. Akt1 knockout plants essentially lacked inward rectifying K+ currents. In contrast, inward rectifying K+ currents were present in AtKC1 knockout plants, but fundamentally altered with respect to gating and cation sensitivity. This indicates that the AtKC1 -subunit represents an integral component of functional root hair K+ uptake channels.
