Inositol 1,4,5 trisphosphate is inactivated by a 5-phosphatase in stamen hair cells of Tradescantia

DePass, Anthony L.; Crain, Richard C.; Hepler, Peter K.

doi:10.1007/s004250100526

Cited by 3 publications

(1 citation statement)

References 27 publications

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“…Interestingly, this effect can also be produced by the addition of caged inositol 1,4,5-trisphosphate. release of Ca 2þ from cellular stores (Depass et al, 2001), and the observation that inositol 1,4,5-trisphosphate can substitute for sperm extract suggests that Ca 2þ accumulation and oscillation may have its origin in signal-transduction signals transmitted by the male during gamete fusion. Stimulation of the female target cells by sperm extract suggests that sperm cells contain a trigger for releasing egg stores of Ca 2þ that may activate a myriad of Ca 2þ channels in both plants and animals.…”

Section: Activation Of the Egg Cell And Calcium Signalingmentioning

confidence: 99%

Calcium function and distribution during fertilization in angiosperms

Tian²,

Russell³

2007

American J of Botany

111

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Calcium has an essential signaling, physiological, and regulatory role during sexual reproduction in flowering plants; elevation of calcium amounts is an accurate predictor of plant fertility. Calcium is present in three forms: (1) covalently bound calcium, (2) loosely bound calcium typically associated with fixed and mobile anions (ionic bonding); and (3) cytosolic free calcium-an important secondary messenger in cell signaling. Pollen often requires calcium for germination. Pollen tube elongation typically relies on external calcium stores in the pistil. Calcium establishes polarity of the pollen tube and forms a basis for pulsatory growth. Applying calcium on the tip may alter the axis; thus calcium may have a role in determining the directionality of tube elongation. In the ovary and ovule, an abundance of calcium signals receptivity, provides essential mineral nutrition, and guides the pollen tube in some plants. Calcium patterns in the embryo sac also correspond to synergid receptivity, reflecting programmed cell death in one synergid cell that triggers degeneration and prepares this cell to receive the pollen tube. Male gametes are released in the synergid, and fusion of the gametes requires calcium, according to in vitro fertilization studies. Fusion of plant gametes in vitro triggers calcium oscillations evident in both the zygote and primary endosperm during double fertilization that are similar to those in animals.

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Section: Activation Of the Egg Cell And Calcium Signalingmentioning

confidence: 99%

Calcium function and distribution during fertilization in angiosperms

Tian²,

Russell³

2007

American J of Botany

111

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Inositol trisphosphate receptor in higher plants: is it real?

Krinke

Novotná

Valentová

et al. 2006

Journal of Experimental Botany

107

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The receptor for D-myo-inositol 1,4,5-trisphosphate (InsP3-R) has been well documented in animal cells. It constitutes an important component of the intracellular calcium signalling system. Today the corresponding genes in many species have been sequenced and the antibodies against some of the InsP3-Rs are available. In contrast, very little is known about its plant counterpart. Only a few published works have dealt directly with this topic. This review summarizes the available relevant data and determines some properties of putative plant receptor(s) including the in silico search for its gene in plant genomes, in vivo evidence, its electrophysiology, the parameters of InsP3-induced calcium release and InsP3 binding, immunological cross-reactivity, and subcellular localization. Future progress in this area seems to be inevitable as, despite the efforts, its gene in plants has not been identified yet.

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Up-Regulation of Phosphoinositide Metabolism in Tobacco Cells Constitutively Expressing the Human Type I Inositol Polyphosphate 5-Phosphatase

et al. 2002

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To evaluate the impact of suppressing inositol 1,4,5-trisphosphate (InsP 3 ) in plants, tobacco (Nicotiana tabacum) cells were transformed with the human type I inositol polyphosphate 5-phosphatase (InsP 5-ptase), an enzyme which specifically hydrolyzes InsP 3 . The transgenic cell lines showed a 12-to 25-fold increase in InsP 5-ptase activity in vitro and a 60% to 80% reduction in basal InsP 3 compared with wild-type cells. Stimulation with Mas-7, a synthetic analog of the wasp venom peptide mastoparan, resulted in an approximately 2-fold increase in InsP 3 in both wild-type and transgenic cells. However, even with stimulation, InsP 3 levels in the transgenic cells did not reach wild-type basal values, suggesting that InsP 3 signaling is compromised. Analysis of whole-cell lipids indicated that phosphatidylinositol 4,5-bisphosphate (PtdInsP 2 ), the lipid precursor of InsP 3 , was greatly reduced in the transgenic cells. In vitro assays of enzymes involved in PtdInsP 2 metabolism showed that the activity of the PtdInsP 2 -hydrolyzing enzyme phospholipase C was not significantly altered in the transgenic cells. In contrast, the activity of the plasma membrane PtdInsP 5 kinase was increased by approximately 3-fold in the transgenic cells. In vivo labeling studies revealed a greater incorporation of 32 P into PtdInsP 2 in the transgenic cells compared with the wild type, indicating that the rate of PtdInsP 2 synthesis was increased. These studies show that the constitutive expression of the human type I InsP 5-ptase in tobacco cells leads to an up-regulation of the phosphoinositide pathway and highlight the importance of PtdInsP 2 synthesis as a regulatory step in this system.In plants the phosphoinositide (PI) pathway has been implicated in the transduction of signals after a multitude of stimuli (Drøbak, 1992; Munnik et al., 1998a;Stevenson et al., 2000). Upon stimulation, the membrane-associated phospholipid, phosphatidylinositol 4,5-bisphosphate (PtdInsP 2 ), is hydrolyzed by phospholipase C (PLC) to produce inositol 1,4,5-trisphosphate (InsP 3 ) and diacylglycerol (Berridge, 1993). InsP 3 can act as a soluble second messenger to mediate the release of Ca 2ϩ from intracellular stores, such as the vacuole (for review, see Sanders et al., 1999). Furthermore, because InsP 3 can travel between cells through plasmodesmatal connections (Tucker and Boss, 1996), it fulfills the requirements for a rapidly diffusible signaling molecule in both intraand intercellular signal propagation.Rapid transient increases in InsP 3 have been demonstrated in various plant tissues in response to environmental stimuli and chemical effectors, including hyperosmotic stress (Srivastava et al., 1989; Heilmann et al., 1999 Heilmann et al., , 2001 DeWald et al., 2001;Takahashi et al., 2001), salinity (Drøbak and Watkins, 2000), cold shock (Smolenska-Sym and Kacperska, 1996), oligogalacturonide elicitors (Legendre et al., 1993), fusicoccin (Aducci and Marra, 1990), mastoparan (Legendre et al., 1993; Drøbak and Watkins, 1994; Cho et a...

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Inositol 1,4,5 trisphosphate is inactivated by a 5-phosphatase in stamen hair cells of Tradescantia

Cited by 3 publications

References 27 publications

Calcium function and distribution during fertilization in angiosperms

Calcium function and distribution during fertilization in angiosperms

Inositol trisphosphate receptor in higher plants: is it real?

Up-Regulation of Phosphoinositide Metabolism in Tobacco Cells Constitutively Expressing the Human Type I Inositol Polyphosphate 5-Phosphatase

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