Collaborative Research: Modeling The Regulatory Network Of Inositol Phosphate Signaling In Plants.
Imara Y. Perera
Joel J. Ducoste
Project runs from 08/15/2016 to 12/31/2019
Myo-inositol phosphates (InsPs) are signaling molecules that are critically important in a number of developmental, metabolic and signaling processes in eukaryotes. The fully phosphorylated form, inositol hexakisphosphate or InsP6, plays important roles in many eukaryotes. A new frontier for InsP signaling is the study of unique signaling roles for a novel group of InsPs containing diphospho- or triphospho- moieties (PPx) at one or more positions on the Ins ring. In some ways, these PPx-InsPs are analogous to ATP in that they contain high-energy pyrophosphate bonds, and in addition, have been linked to communicating the energy status of the cell in other organisms. In this collaborative project, we previously developed analytical methods to detect and quantify PPx-InsPs in plant tissues, identified and cloned genes encoding the VIP kinases that are responsible for inositol pyrophosphate production in plants, and developed genetic resources to examine function of the Vip genes. Our preliminary data using mutants lacking both Vip genes reveal these genes are key in signaling the energy status of the plant cell. Further, we have identified a possible mechanistic link between inositol pyrophosphate signaling and a major regulator of eukaryotic metabolism, the Sucrose non-fermenting related kinase 1 (SnRK1). Given the immediate need to understand and manipulate plant bioenergy, the long-term goal of this project is to understand how InsP6, InsP7 and InsP8 convey signaling information within the cell. We focus on these molecules in plants, but point out that our model and findings are applicable to understanding the InsP6 signaling hub in other eukaryotes. During the proposed project, we plan to address several unresolved questions pertaining to PPx-InsPs and energy by first adding to a preliminary kinetic model of this signaling pathway.