The flip side of phospho‐signalling: Regulation of protein dephosphorylation and the protein phosphatase 2Cs

Abstract

Protein phosphorylation is a key signalling mechanism and has myriad effects on protein function. Phosphorylation by protein kinases can be reversed by protein phosphatases, thus allowing dynamic control of protein phosphorylation. Although this may suggest a straightforward kinase-phosphatase relationship, plant genomes contain five times more kinases than phosphatases. Here, we examine phospho-signalling from a protein phosphatase centred perspective and ask how relatively few phosphatases regulate many phosphorylation sites. The most abundant class of plant phosphatases, the protein phosphatase 2Cs (PP2Cs), is surrounded by a web of regulation including inhibitor and activator proteins as well as posttranslational modifications that regulate phosphatase activity, control phosphatase stability, or determine the subcellular locations where the phosphatase is present and active. These mechanisms are best established for the Clade A PP2Cs, which are key components of stress and abscisic acid signalling.We also describe other PP2C clades and illustrate how these phosphatases are highly regulated and involved in a wide range of physiological functions. Together, these examples of multiple layers of phosphatase regulation help explain the unbalanced kinase-phosphatase ratio. Continued use of phosphoproteomics to examine phosphatase targets and phosphatase-kinase relationships will be important for deeper understanding of phosphoproteome regulation.

Selection and validation of reference genes for measuring gene expression in Toona ciliata under different experimental conditions by quantitative real-time PCR analysis

“…3 Pairwise variations (V) for the 20 candidate reference genes calculated by geNorm to determine the optimal number of reference genes for accurate normalization. The threshold used was 0.15 phosphatase in plants [49]. Although it not often has been used as a candidate internal reference gene, it is stable in our study under pest stress and in different tissues for GA treatment of Santalum album [50].…”

“…Hence, it is necessary to identify the best reference genes for specific conditions via RT-qPCR. Protein phosphatase can reverse the phosphorylation of protein kinases, thereby dynamically controlling protein phosphorylation and protein phosphatase 2Cs ( PP2Cs ) is the most abundant type of phosphatase in plants [ 49 ]. Although it not often has been used as a candidate internal reference gene, it is stable in our study under pest stress and in different tissues for GA treatment of Santalum album [ 50 ].…”

Selection and validation of reference genes for measuring gene expression in Toona ciliata under different experimental conditions by quantitative real-time PCR analysis

“…Hence, it is necessary to identify the best reference genes for speci c conditions via RT-qPCR. Protein phosphatase can reverse the phosphorylation of protein kinases, thereby dynamically controlling protein phosphorylation and protein phosphatase 2Cs (PP2Cs) is the most abundant type of phosphatase in plants [49]. Although it not often has been used as a candidate internal reference gene, it is stable in our study under pest stress and in different tissues for GA treatment of Santalum album [50].…”

An Avirulent Strain of Soybean Mosaic Virus Reverses the Defensive Effect of Abscisic Acid in a Susceptible Soybean Cultivar

“…ROP11 is also a negative regulator of ABA responses, and ABA-mediated responses are downregulated when ROP11 is constitutively expressed [39]. Other negative regulators of the ABA signaling pathway include members of the PP2C clade, such as ABI1, ABI2, and PP2C3a [40]. ABA perception by the receptor PYR/PYL/RCAR requires specific PP2C proteins (ABI1 and ABI2) to form one large complex.…”