Molecular Characterization of an Arabidopsis Gene Encoding a Phospholipid-Specific Inositol Polyphosphate 5-Phosphatase

Ercetin, Mustafa; Gillaspy, Glenda E.

doi:10.1104/pp.104.040253

Cited by 56 publications

(82 citation statements)

References 36 publications

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“…In vitro, At5PTase11 and AtSAC1/FRA7 have been shown to dephosphorylate PtdIns(3,5)P 2 at the 5-position (52). AtSAC1/FRA7 mutants have defects in the organization of the actin cytoskeleton and exhibit reduced cell wall thickening (53).…”

Section: Plant Phospholipid Signaling S263mentioning

confidence: 99%

Plant phospholipid signaling: “in a nutshell”

Munnik

Testerink

2009

Journal of Lipid Research

249

214

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Since the discovery of the phosphoinositide/ phospholipase C (PI/PLC) system in animal systems, we know that phospholipids are much more then just structural components of biological membranes. In the beginning, this idea was fairly straightforward. Receptor stimulation activates PLC, which hydrolyses phosphatidylinositol4,5-bisphosphate [PtdIns(4,5)P 2 ] into two second messengers: inositol 1,4,5-trisphosphate (InsP 3 ) and diacylglycerol (DG). While InsP 3 difuses into the cytosol and triggers the release of calcium from an internal store via ligand-gated calcium channels, DG remains in the membrane where it recruits and activates members of the PKC family. The increase in calcium, together with the change in phosphorylation status, (in)activates a variety of protein targets, leading to a massive reprogramming, allowing the cell to appropriately respond to the extracellular stimulus. Later, it became obvious that not just PLC, but a variety of other phospholipid-metabolizing enzymes were activated, including phospholipase A, phospholipase D, and PI 3-kinase.

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Section: Plant Phospholipid Signaling S263mentioning

confidence: 99%

Plant phospholipid signaling: “in a nutshell”

Munnik

Testerink

2009

Journal of Lipid Research

249

214

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“…Plant extracts were made by freezing in N 2(l) , followed by grinding in Laemmle gel-loading buffer containing SDS and b-mercaptoethanol for denaturing gel fractionation, or alone for native gels. Lysates were analyzed by protein gel blotting as described previously (Burnette et al, 2003;Ercetin and Gillaspy, 2004) except that nonfat dry milk was used for blocking and a 1:20,000 dilution of anti-MIPS antibody or 1:1000 dilution of anti-GFP antibody (Invitrogen) was used.…”

Section: Protein Blot Analysesmentioning

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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“…Several of the At5PTase proteins have been examined biochemically and the results reveal that these enzymes vary in their substrate specificity (Berdy et al, 2001;Ercetin and Gillaspy, 2004;. For example, At5PTase1 and At5PTase2 enzymes have been reported to hydrolyze water-soluble substrates Ins(1,4,5)P 3 and Ins(1,3,4,5)P 4 in vitro (Berdy et al, 2001), whereas the At5PTase11 enzyme preferentially hydrolyzes lipid substrates containing a 5-P such as PtdIns(4,5)P 2 (Ercetin and Gillaspy, 2004). Other characterized At5PTases have been shown to hydrolyze both types of substrates .…”

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confidence: 99%

Inositol Polyphosphate 5-Phosphatases 1 and 2 Are Required for Regulating Seedling Growth

et al. 2007

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Signals can be perceived and amplified at the cell membrane by receptors coupled to the production of a variety of second messengers, including myoinositol 1,4,5-trisphosphate [Ins(1,4,5)P 3 ]. The myoinositol polyphosphate 5-phosphatases (5PTases; EC 3.1.3.56) comprise a large protein family that hydrolyzes 5-phosphates from a variety of myoinositol phosphate (InsP) and phosphoinositide phosphate (PtdInsP) substrates. Arabidopsis thaliana has 15 genes encoding 5PTases. Biochemical analyses of a subgroup of 5PTase enzymes suggest that these enzymes have both overlapping and unique substrate preferences. Ectopic expression of these genes in transgenic plants can reduce Ins(1,4,5)P 3 levels and alter abscisic acid (ABA) signaling. To further explore the function of 5PTases in signaling, we have identified and characterized T-DNA insertional mutants for 5PTase1 and 5PTase2 and produced a double mutant. When grown in the dark, the seeds from these mutants germinate faster than wildtype seeds and the mutant seedlings have longer hypocotyls than wild-type seedlings. Seeds from these mutant lines also demonstrate an increase in sensitivity to ABA. These changes in early seedling growth are accompanied by mass increases in Ins(1,4,5)P 3 , but not by changes in endogenous ABA content. By labeling the endogenous myoinositol pool in 5ptase1 and 5ptase2 mutants, we detected increases in Ins(1,4,5)P 3 and a decrease in PtdIns, PtdIns(4)P, and phosphatidylinositol (4,5) bisphosphate. Taken together, these data indicate that the At5PTase1 and At5PTase2 genes have nonredundant roles in hydrolyzing inositol second-messenger substrates and that regulation of Ins(1,4,5)P 3 levels is important during germination and early seedling development.

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Molecular Characterization of an Arabidopsis Gene Encoding a Phospholipid-Specific Inositol Polyphosphate 5-Phosphatase

Cited by 56 publications

References 36 publications

Plant phospholipid signaling: “in a nutshell”

Plant phospholipid signaling: “in a nutshell”

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

Inositol Polyphosphate 5-Phosphatases 1 and 2 Are Required for Regulating Seedling Growth

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