Abscisic acid: emergence of a core signaling network.
Abscisic acid (ABA) regulates numerous developmental processes and adaptive stress responses in plants. Many ABA signaling components have been identified, but their interconnections and a consensus on the structure of the ABA signaling network have eluded researchers. Recently, several advances have led to the identification of ABA receptors and their three-dimensional structures, and an understanding of how key regulatory phosphatase and kinase activities are controlled by ABA. A new model for ABA action has been proposed and validated, in which the soluble PYR/PYL/RCAR receptors function at the apex of a negative regulatory pathway to directly regulate PP2C phosphatases, which in turn directly regulate SnRK2 kinases. This model unifies many previously defined signaling components and highlights the importance of future work focused on defining the direct targets of SnRK2s and PP2Cs, dissecting the mechanisms of hormone interactions (i.e., cross talk) and defining connections between this new negative regulatory pathway and other factors implicated in ABA signaling.
Cutler
Sean R
SR
Department of Botany and Plant Sciences, University of California, Riverside, California 92521, USA. sean.cutler@ucr.edu
Rodriguez
Pedro L
PL
Finkelstein
Ruth R
RR
Abrams
Suzanne R
SR
D000040:Abscisic Acid / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D010944:Plants / Q000378:metabolism*; D015398:Signal Transduction
D000040:Abscisic Acid