RH8-PP2CA interaction in ABA signaling ($)

It is well understood that abscisic acid (ABA) inhibits PPC2A phosphatase activity, which subsequently relieves phosphate-induced inhibition of a kinase interacting partner. This pathway composes the ‘core’ ABA signaling pathway, activating process involved in the ABA response such as stomatal closure to preserve water loss. Baek et al. identified an additional player in this core ABA pathway via yeast two-hybrid screening for PP2CA interactors: the DEAD-box RNA helicase, RH8. Interestingly, while the above pathway occurs in the cytoplasm, RH8 was found to interact with PP2CA in the nucleus.  Furthermore, rh8 mutants are hyposensitive to ABA and display reduced stomatal closure while rh8 pp2ca double mutants display the opposite phenotype: ABA hypersensitive and drought tolerance. This paper adds to the core ABA signaling pathway, introducing RH8 as an inhibitor of PP2CA phosphatase activity (Summary by Alecia Biel) Plant, Cell, & Enviorn. 10.1111/pce.13200