Genetics of Inositol Polyphosphates

Raboy, Victor; Bowen, David

doi:10.1007/0-387-27600-9_4

Cited by 23 publications

(23 citation statements)

References 114 publications

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“…In multicellular eukaryotes, myo-inositol becomes incorporated into phosphatidylinositol phosphate (PtdInsP), myo-inositol phosphate (InsP), and certain sphingolipid signaling molecules that function in many processes, such as regulation of gene expression (Alcazar-Roman and Wente, 2008), phosphorus storage (Raboy and Bowen, 2006), auxin receptor association (Tan et al, 2007), membrane tethering (Fujita and Jigami, 2008), stress tolerance (Taji et al, 2006), oligosaccharide synthesis (galactinol) (Karner et al, 2004;Michell, 2007), and regulation of cell death (sphingolipids) Liang et al, 2003). The oxidation product of myo-inositol (D-glucuronic acid) is used for cell wall pectic noncellulosic compounds (Loewus et al, 1962;Loewus, 1965Loewus, , 2006 and, in some organisms, for synthesis of ascorbic acid (Baig et al, 1970;Allison and Stewart, 1973;Banhegyi et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

TheArabidopsis thaliana Myo-Inositol 1-Phosphate Synthase1 Gene Is Required forMyo-inositol Synthesis and Suppression of Cell Death

et al. 2010

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L-myo-inositol 1-phosphate synthase (MIPS; EC 5.5.1.4) catalyzes the rate-limiting step in the synthesis of myo-inositol, a critical compound in the cell. Plants contain multiple MIPS genes, which encode highly similar enzymes. We characterized the expression patterns of the three MIPS genes in Arabidopsis thaliana and found that MIPS1 is expressed in most cell types and developmental stages, while MIPS2 and MIPS3 are mainly restricted to vascular or related tissues. MIPS1, but not MIPS2 or MIPS3, is required for seed development, for physiological responses to salt and abscisic acid, and to suppress cell death. Specifically, a loss in MIPS1 resulted in smaller plants with curly leaves and spontaneous production of lesions. The mips1 mutants have lower myo-inositol, ascorbic acid, and phosphatidylinositol levels, while basal levels of inositol (1,4,5)P 3 are not altered in mips1 mutants. Furthermore, mips1 mutants exhibited elevated levels of ceramides, sphingolipid precursors associated with cell death, and were complemented by a MIPS1-green fluorescent protein (GFP) fusion construct. MIPS1-, MIPS2-, and MIPS3-GFP each localized to the cytoplasm. Thus, MIPS1 has a significant impact on myo-inositol levels that is critical for maintaining levels of ascorbic acid, phosphatidylinositol, and ceramides that regulate growth, development, and cell death.

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Section: Introductionmentioning

confidence: 99%

TheArabidopsis thaliana Myo-Inositol 1-Phosphate Synthase1 Gene Is Required forMyo-inositol Synthesis and Suppression of Cell Death

et al. 2010

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“…InsP 6 , the most abundant inositol phosphate in plants, has several cell-signaling functions [1], and is also a structural cofactor for the auxin receptor [2]. Additionally, InsP 6 is a phosphate storage compound, so it accumulates to considerable levels in plant seeds [1].…”

Section: Introductionmentioning

confidence: 99%

“…Another important problem is that phytate-rich soybeans, grains and other plant seeds are widely used as the primary protein source in feed for monogastric farm animals [3]. Undigested InsP 6 phosphorus is excreted in manure, which is applied to pastures and croplands. Runoff from agricultural fields can result in environmental phosphorus pollution, eutrophication and impaired water quality [4,5].…”

Section: Introductionmentioning

confidence: 99%

“…Runoff from agricultural fields can result in environmental phosphorus pollution, eutrophication and impaired water quality [4,5]. Therefore, there is considerable interest in using molecular genetics to generate crops in which InsP 6 synthesis during seed development is disrupted [1]. However, it is first necessary to identify the enzymes in this biosynthetic pathway.…”

Section: Introductionmentioning

confidence: 99%

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Metabolic and signaling properties of an Itpk gene family in Glycine max

et al. 2008

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We have cloned and characterized four Itpk genes from soybean. All four recombinant Itpk proteins showed canonical Ins(1,3,4)P 3 5/6-kinase activity, but a kinetic analysis raised questions about its biological significance. Instead, we provide evidence that one alternative biological role for soybean Itpks is to interconvert the Cl À channel inhibitor, Ins(3,4,5,6)P 4 , and its metabolic precursor, Ins(1,3,4,5,6)P 5 , within a substrate cycle. The soybean Itpks also phosphorylated Ins(3,4,6)P 3 to Ins(1,3,4,6)P 4 which was further phosphorylated to Ins(1,3,4,5,6)P 5 by soybean Ipk2. Thus, soybean Itpks may participate in an inositol lipid-independent pathway of InsP 6 synthesis.

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“…In multiceullar eukaryotes, myoinositol becomes incorporated into many crucial cellular compounds, including those involved in signal transduction such as phosphatidylinositol phosphates and myoinositol phosphates (InsPs; for review, see Boss et al, 2006), gene expression (InsPs; for review, see Alcazar-Roman and Wente, 2007), auxin perception and phosphorus storage (myoinositol hexakisphosphate [InsP 6 ]; for review, see Raboy and Bowen, 2006;Tan et al, 2007), membrane tethering (glycerophosphoinositide anchors; for review, see Fujita and Jigami, 2007), stress tolerance (ononitol, pinitol; for review, see Taji et al, 2006), and oligosaccharide synthesis (galactinol; for review, see Karner et al, 2004;Fig. 1).…”

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confidence: 99%

VTC4 Is a Bifunctional Enzyme That Affects Myoinositol and Ascorbate Biosynthesis in Plants

et al. 2009

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Myoinositol synthesis and catabolism are crucial in many multiceullar eukaryotes for the production of phosphatidylinositol signaling molecules, glycerophosphoinositide membrane anchors, cell wall pectic noncellulosic polysaccharides, and several other molecules including ascorbate. Myoinositol monophosphatase (IMP) is a major enzyme required for the synthesis of myoinositol and the breakdown of myoinositol (1,4,5)trisphosphate, a potent second messenger involved in many biological activities. It has been shown that the VTC4 enzyme from kiwifruit (Actinidia deliciosa) has similarity to IMP and can hydrolyze L-galactose 1-phosphate (L-Gal 1-P), suggesting that this enzyme may be bifunctional and linked with two potential pathways of plant ascorbate synthesis. We describe here the kinetic comparison of the Arabidopsis (Arabidopsis thaliana) recombinant VTC4 with D-myoinositol 3-phosphate (D-Ins 3-P) and L-Gal 1-P. Purified VTC4 has only a small difference in the V max /K m for L-Gal 1-P as compared with D-Ins 3-P and can utilize other related substrates. Inhibition by either Ca 2+ or Li + , known to disrupt cell signaling, was the same with both L-Gal 1-P and D-Ins 3-P. To determine whether the VTC4 gene impacts myoinositol synthesis in Arabidopsis, we isolated T-DNA knockout lines of VTC4 that exhibit small perturbations in abscisic acid, salt, and cold responses. Analysis of metabolite levels in vtc4 mutants showed that less myoinositol and ascorbate accumulate in these mutants. Therefore, VTC4 is a bifunctional enzyme that impacts both myoinositol and ascorbate synthesis pathways.

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Genetics of Inositol Polyphosphates

Cited by 23 publications

References 114 publications

TheArabidopsis thaliana Myo-Inositol 1-Phosphate Synthase1 Gene Is Required forMyo-inositol Synthesis and Suppression of Cell Death

TheArabidopsis thaliana Myo-Inositol 1-Phosphate Synthase1 Gene Is Required forMyo-inositol Synthesis and Suppression of Cell Death

Metabolic and signaling properties of an Itpk gene family in Glycine max

VTC4 Is a Bifunctional Enzyme That Affects Myoinositol and Ascorbate Biosynthesis in Plants

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