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A Strategy to Validate the Role of Callose-mediated Plasmodesmal Gating in the Tropic Response
Published on: April 17, 2016
The Arabidopsis guard cell outward potassium channel GORK is regulated by CPK33
Claire Corratgé-Faillie1, Elsa Ronzier1, Frédéric Sanchez1
1Biochimie et Physiologie Moléculaire des Plantes, UMR CNRS/INRA/Montpellier SupAgro/UM, Montpellier, France.
Abstract:
A complex signaling network involving voltage-gated potassium channels from the Shaker family contributes to the regulation of stomatal aperture. Several kinases and phosphatases have been shown to be crucial for ABA-dependent regulation of the ion transporters. To date, the Ca2+ -dependent regulation of Shaker channels by Ca2+ -dependent protein kinases (CPKs) is still elusive. A functional screen in Xenopus oocytes was launched to identify such CPKs able to regulate the three main guard cell Shaker channels KAT1, KAT2, and GORK. Seven guard cell CPKs were tested and multiple CPK/Shaker couples were identified. Further work on CPK33 indicates that GORK activity is enhanced by CPK33 and unaffected by a nonfunctional CPK33 (CPK33-K102M). Furthermore, Ca2+ -induced stomatal closure is impaired in two cpk33 mutant plants.
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