Phosphatidyl inositol metabolism and its role in signal transduction in growing plants

Lehle, Ludwig

doi:10.1007/bf00017839

Cited by 41 publications

(16 citation statements)

References 105 publications

(119 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…We have identified myoinositol as an initial substrate for AsA biosynthesis (Lorence et al, 2004), while others have shown it to be a precursor for the synthesis of the nucleotide sugar UDP-GlcUA, which participates in the production of residues of plant cell walls (Loewus and Murthy, 2000;Kanter et al, 2005). Moreover, as a component of phospholipids, myoinositol is involved in several signaling pathways (Lehle, 1990). Despite these essential functions of myoinositol in plant biology, little is known about the partitioning of this molecule between different cells, tissues, or subcellular compartments.…”

Section: Discussionmentioning

confidence: 99%

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

et al. 2007

View full text Add to dashboard Cite

Ascorbate (AsA) is the most abundant antioxidant in plant cells and a cofactor for a large number of key enzymes. However, the mechanism of how AsA levels are regulated in plant cells remains unknown. The Arabidopsis (Arabidopsis thaliana) activationtagged mutant AT23040 showed a pleiotropic phenotype, including ozone resistance, rapid growth, and leaves containing higher AsA than wild-type plants. The phenotype was caused by activation of a purple acid phosphatase (PAP) gene, AtPAP15, which contains a dinuclear metal center in the active site. AtPAP15 was universally expressed in all tested organs in wild-type plants. Overexpression of AtPAP15 with the 35S cauliflower mosaic virus promoter produced mutants with up to 2-fold increased foliar AsA, 20% to 30% decrease in foliar phytate, enhanced salt tolerance, and decreased abscisic acid sensitivity. Two independent SALK T-DNA insertion mutants in AtPAP15 had 30% less foliar AsA and 15% to 20% more phytate than wild-type plants and decreased tolerance to abiotic stresses. Enzyme activity of partially purified AtPAP15 from plant crude extract and recombinant AtPAP15 expressed in bacteria and yeast was highest when phytate was used as substrate, indicating that AtPAP15 is a phytase. Recombinant AtPAP15 also showed enzyme activity on the substrate myoinositol-1-phosphate, indicating that the AtPAP15 is a phytase that hydrolyzes myoinositol hexakisphosphate to yield myoinositol and free phosphate. Myoinositol is a known precursor for AsA biosynthesis in plants. Thus, AtPAP15 may modulate AsA levels by controlling the input of myoinositol into this branch of AsA biosynthesis in Arabidopsis.

show abstract

Section: Discussionmentioning

confidence: 99%

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

et al. 2007

View full text Add to dashboard Cite

show abstract

“…Plant phosphoinositide metabolism shows many similarities to the metabolism involved in mammalian polyphosphoinositide transmembrane signaling systems (8,12,25). In …”

Section: Materials and Methods Materialsmentioning

confidence: 99%

Polyphosphoinositide Phospholipase C in Plasma Membranes of Wheat (Triticum aestivum L.)

Pical

Sandelius²,

Melin³

et al. 1992

Plant Physiol.

View full text Add to dashboard Cite

Polyphosphoinositide-specific phospholipase C activity was present in plasma membranes isolated from different tissues of several higher plants. Phospholipase C activities against added phosphatidylinositol 4-phosphate (PIP) and phosphatidylinositol 4,5-bisphosphate (PIP2) were further characterized in plasma membrane fractions isolated from shoots and roots of dark-grown wheat (Triticum aestivum L. cv Drabant) seedlings. In right-side-out (70-80% apoplastic side out) plasma membrane vesicles, the activities were increased 3 to 5 times upon addition of 0.01 to 0.025% (w/ v) sodium deoxycholate, whereas in fractions enriched in insideout (70-80% cytoplasmic side out) vesicles, the activities were only slightly increased by detergent. Furthermore, the activities of inside-out vesicles in the absence of detergent were very close to those of right-side-out vesicles in the presence of optimal detergent concentration. This verifies the general assumption that polyphosphoinositide phospholipase C activity is located at the cytoplasmic surface of the plasma membrane. PIP and PIP2 phospholipase C was dependent on Ca21 with maximum activity at 10 to 100 Mm free Ca2 and half-maximal activation at 0.1 to 1 Mm free Ca2. In the presence of 10 gM Ca21, 1 to 2 mM MgCI2 or MgSO4 further stimulated the enzyme activity. The other divalent chloride salts tested (1.5 mm Ba2", Co2+, Cu2+, Mn2+, Ni2+, and Zn2+) inhibited the enzyme activity. The stimulatory effect by Mg2+ was observed also when 35 mm NaCI was included. Thus, the PIP and PIP2 phospholipase C exhibited maximum in vitro activity at physiologically relevant ion concentrations. The plant plasma membrane also possessed a phospholipase C activity against phosphatidylinositol that was 40 times lower than that observed with PIP or PIP2 as substrate. The phosphatidylinositol phospholipase C activity was dependent on Ca2 , with maximum activity at 1 mm CaC12, and could not be further stimulated by Mg2+.animal cells, phospholipase C-catalyzed production of the second messengers inositol 1,4,5-trisphosphate and diacylglycerol from PIP22 is a key event in the transduction of agonist-dependent signals over the plasma membrane (1,3,15). PIP2 is formed by a two-step phosphorylation of PI by PI kinase and PIP kinase, enzymes that are also present in plant plasma membranes (18,24,29). Because phospholipase C, preferentially active on PIP and PIP2, has also been identified in plasma membranes from plants (7,17,30), there is an enzymic basis for signal transduction through hydrolysis of polyphosphoinositides. However, very little is known about the mechanism operating in the plant plasma membrane, in part due to the scant knowledge about phospholipase C.In this communication, we present evidence for the localization of polyphosphoinositide phospholipase C activity in wheat (Triticum aestivum L. cv Drabant) plasma membranes to the cytoplasmic surface of the membrane. We also present a further characterization of the in vitro properties of the enzyme activity. MATERIALS AND METHODS

show abstract

“…light, osmotic stress) and to several phytohormones could be mediated by these messengers (reviewed by Lehle 1990;Einspahr and Thompson 1990;Trewavas and Gilroy 1991).…”

Section: Introductionmentioning

confidence: 99%

Rapid turnover of polyphosphoinositides in carnation flower petals

Munnik¹,

Musgrave

Vrije³

1994

Planta

View full text Add to dashboard Cite

Abstract. Carnation (Dianthus caryophyllus L. cv. White Sim) petal discs were radiolabelled with [32p]orthophosphate and the lipids were extracted and analysed by thin-layer chromatography and autoradiography. Phospholipids were identified by co-migration with standards using thin-layer chromatography with different solvent systems. Results showed that [32p]orthophosphate was rapidly incorporated into the minor lipids phosphatidic acid (PtdOH), phosphatidylinositol monophosphate (PtdInsP) and phosphatidylinositol bisphosphate (PtdInsP2), and relatively slowly into the structural lipids phosphatidylcholine, -ethanolamine, -glycerol and -inositol. Pulse-chase experiments revealed that the label was rapidly lost from PtdOH, PtdInsP and PtdInsP2 while the structural lipids remained radiolabelled. The amount of PtdInsP and PtdInsP2 was found to constitute 0.45% and 0.013%, respectively, of the total phospholipids, on a molar basis. Together these results show that the turnover of the chemically low-abundant polyphosphoinositides is relatively high compared with the major structural phospholipids. Phosphatidylinositol monophosphate was further characterized by showing that it incorporates myo-[3H]inositol and that its major fatty-acid constituents are palmitic acid and linoleic acid. Furthermore, we present evidence for the presence of both phosphatidylinositol 3-phosphate and phosphatidylinositol 4-phosphate isomers. The significance of these results is discussed with respect to plant phosphoinositide signal transduction.

show abstract

Phosphatidyl inositol metabolism and its role in signal transduction in growing plants

Cited by 41 publications

References 105 publications

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

An Arabidopsis Purple Acid Phosphatase with Phytase Activity Increases Foliar Ascorbate

Polyphosphoinositide Phospholipase C in Plasma Membranes of Wheat (Triticum aestivum L.)

Rapid turnover of polyphosphoinositides in carnation flower petals

Contact Info

Product

Resources

About