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Biosynthesis and possible functions of inositol pyrophosphates in plants.

Williams SP, Gillaspy GE, Perera IY - Front Plant Sci (2015)

Bottom Line: Most eukaryotes synthesize the precursor molecule, myo-inositol (1,2,3,4,5,6)-hexakisphosphate (InsP6), which can serve as a signaling molecule or as storage compound of inositol, phosphorus, and minerals (referred to as phytic acid).Recent work has delineated that Arabidopsis has two genes capable of PP-InsP5 synthesis, and PPx-InsPs have been detected across the plant kingdom.This review will detail the known roles of PPx-InsPs in yeast and animal systems, and provide a description of recent data on the synthesis and accumulation of these novel molecules in plants, and potential roles in signaling.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry, Virginia Polytechnic and State University Blacksburg, VA, USA.

ABSTRACT
Inositol phosphates (InsPs) are intricately tied to lipid signaling, as at least one portion of the inositol phosphate signaling pool is derived from hydrolysis of the lipid precursor, phosphatidyl inositol (4,5) bisphosphate. The focus of this review is on the inositol pyrophosphates, which are a novel group of InsP signaling molecules containing diphosphate or triphosphate chains (i.e., PPx) attached to the inositol ring. These PPx-InsPs are emerging as critical players in the integration of cellular metabolism and stress signaling in non-plant eukaryotes. Most eukaryotes synthesize the precursor molecule, myo-inositol (1,2,3,4,5,6)-hexakisphosphate (InsP6), which can serve as a signaling molecule or as storage compound of inositol, phosphorus, and minerals (referred to as phytic acid). Even though plants produce huge amounts of precursor InsP6 in seeds, almost no attention has been paid to whether PPx-InsPs exist in plants, and if so, what roles these molecules play. Recent work has delineated that Arabidopsis has two genes capable of PP-InsP5 synthesis, and PPx-InsPs have been detected across the plant kingdom. This review will detail the known roles of PPx-InsPs in yeast and animal systems, and provide a description of recent data on the synthesis and accumulation of these novel molecules in plants, and potential roles in signaling.

No MeSH data available.


Related in: MedlinePlus

A modified tree of life indicating the composition of genes in different species that encode kinases capable of phosphorylating InsP6. Genes in blue have sequence identity with KCS1, whereas genes in red have sequence identity with VIP. The tree depicts evolutionary relationships between groups discussed in the review.
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Figure 3: A modified tree of life indicating the composition of genes in different species that encode kinases capable of phosphorylating InsP6. Genes in blue have sequence identity with KCS1, whereas genes in red have sequence identity with VIP. The tree depicts evolutionary relationships between groups discussed in the review.

Mentions: There are two classes of genes shown to encode enzymes required for synthesis of PPx-InsPs. Figure 3 shows the presence and names of these genes in species relevant to this review. These two classes of genes encode distinct enzymes that catalyze the addition of pyrophosphates at specific positions on the inositol ring (Figure 2). The first class is named the InsP6 kinases (IP6Ks), and the kinase activity of these enzymes phosphorylates the 5-position of InsP5, InsP6, and InsP7, yielding 5PP-InsP4 or 5PP-InsP5 and two possible forms of InsP8: 1/3,5PP-InsP5 and 5PPP-InsP5 (Draskovic et al., 2008). In yeast, this class of enzymes is named KCS1, and was first identified in a suppressor screen of the yeast Protein Kinase C (pkc1) mutant (Huang and Symington, 1995). Kcs1 encodes a protein closely related to the bZIP family of transcription factors, although analysis of its two potential leucine zipper motifs indicates the secondary alpha-helical structure for DNA binding is not formed (Huang and Symington, 1995). Instead, the altered structure of this alpha helix in addition to a two-turn 310 helix, forms a pocket for InsP6 binding (Wang et al., 2014).


Biosynthesis and possible functions of inositol pyrophosphates in plants.

Williams SP, Gillaspy GE, Perera IY - Front Plant Sci (2015)

A modified tree of life indicating the composition of genes in different species that encode kinases capable of phosphorylating InsP6. Genes in blue have sequence identity with KCS1, whereas genes in red have sequence identity with VIP. The tree depicts evolutionary relationships between groups discussed in the review.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4325660&req=5

Figure 3: A modified tree of life indicating the composition of genes in different species that encode kinases capable of phosphorylating InsP6. Genes in blue have sequence identity with KCS1, whereas genes in red have sequence identity with VIP. The tree depicts evolutionary relationships between groups discussed in the review.
Mentions: There are two classes of genes shown to encode enzymes required for synthesis of PPx-InsPs. Figure 3 shows the presence and names of these genes in species relevant to this review. These two classes of genes encode distinct enzymes that catalyze the addition of pyrophosphates at specific positions on the inositol ring (Figure 2). The first class is named the InsP6 kinases (IP6Ks), and the kinase activity of these enzymes phosphorylates the 5-position of InsP5, InsP6, and InsP7, yielding 5PP-InsP4 or 5PP-InsP5 and two possible forms of InsP8: 1/3,5PP-InsP5 and 5PPP-InsP5 (Draskovic et al., 2008). In yeast, this class of enzymes is named KCS1, and was first identified in a suppressor screen of the yeast Protein Kinase C (pkc1) mutant (Huang and Symington, 1995). Kcs1 encodes a protein closely related to the bZIP family of transcription factors, although analysis of its two potential leucine zipper motifs indicates the secondary alpha-helical structure for DNA binding is not formed (Huang and Symington, 1995). Instead, the altered structure of this alpha helix in addition to a two-turn 310 helix, forms a pocket for InsP6 binding (Wang et al., 2014).

Bottom Line: Most eukaryotes synthesize the precursor molecule, myo-inositol (1,2,3,4,5,6)-hexakisphosphate (InsP6), which can serve as a signaling molecule or as storage compound of inositol, phosphorus, and minerals (referred to as phytic acid).Recent work has delineated that Arabidopsis has two genes capable of PP-InsP5 synthesis, and PPx-InsPs have been detected across the plant kingdom.This review will detail the known roles of PPx-InsPs in yeast and animal systems, and provide a description of recent data on the synthesis and accumulation of these novel molecules in plants, and potential roles in signaling.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry, Virginia Polytechnic and State University Blacksburg, VA, USA.

ABSTRACT
Inositol phosphates (InsPs) are intricately tied to lipid signaling, as at least one portion of the inositol phosphate signaling pool is derived from hydrolysis of the lipid precursor, phosphatidyl inositol (4,5) bisphosphate. The focus of this review is on the inositol pyrophosphates, which are a novel group of InsP signaling molecules containing diphosphate or triphosphate chains (i.e., PPx) attached to the inositol ring. These PPx-InsPs are emerging as critical players in the integration of cellular metabolism and stress signaling in non-plant eukaryotes. Most eukaryotes synthesize the precursor molecule, myo-inositol (1,2,3,4,5,6)-hexakisphosphate (InsP6), which can serve as a signaling molecule or as storage compound of inositol, phosphorus, and minerals (referred to as phytic acid). Even though plants produce huge amounts of precursor InsP6 in seeds, almost no attention has been paid to whether PPx-InsPs exist in plants, and if so, what roles these molecules play. Recent work has delineated that Arabidopsis has two genes capable of PP-InsP5 synthesis, and PPx-InsPs have been detected across the plant kingdom. This review will detail the known roles of PPx-InsPs in yeast and animal systems, and provide a description of recent data on the synthesis and accumulation of these novel molecules in plants, and potential roles in signaling.

No MeSH data available.


Related in: MedlinePlus