Polyphosphoinositide metabolism during the fertilization wave in sea urchin eggs

Development ◽  
1992 ◽  
Vol 115 (1) ◽  
pp. 187-195 ◽  
Author(s):  
B. Ciapa ◽  
B. Borg ◽  
M. Whitaker
Keyword(s):  
Sea Urchin ◽  
Calcium Release ◽  
Calcium Ionophore ◽  
Fold Increase ◽  
Calcium Ionophore A23187 ◽  
Calcium Signal ◽  
Free Calcium ◽  
Ionophore A23187 ◽  
Isotopic Equilibrium ◽  
Sea Urchin Eggs

A transient increase in intracellular free calcium is believed to be the signal responsible for the stimulation of the egg metabolism at fertilization and the resumption of the cell cycle. We have studied how the polyphosphoinositides (PPI) turn over at fertilization in sea urchin eggs, in order to determine the relationship between the metabolism of these lipids and the calcium signal. We compare the patterns of PPI turnover that occur during the first minute following fertilization in eggs in which PPI are labelled to steady state with [3H]inositol or [3H]arachidonate with that in which PPI are labelled for a shorter period with [3H]inositol. When eggs are labelled to apparent isotopic equilibrium with either [3H]inositol or [3H]arachidonate, no early increase in [3H]PtdInsP2 occurs while PtdIns decreases slightly. On the contrary, when not labelled to isotopic equilibrium, all [3H]PPI increase during the first 15 seconds following fertilization. We find that, within seconds, fertilization triggers a 600-fold increase in the turnover of PPI, producing an amount of InsP3 apparently sufficient to trigger calcium release. We suggest that phosphoinositidase C and PtdInsP kinase, responsible respectively for the hydrolysis and synthesis of PtdInsP2, are both stimulated to a comparable degree in the first 30 seconds following fertilization and that net changes in the amount of PtdInsP2 at fertilization are very sensitive to the relative levels of activation of the two enzymes. Activating the eggs with the calcium ionophore A23187 showed that both these enzymes are sensitive to calcium, suggesting that calcium-dependent InsP3 production might play a role in the initiation and/or the propagation of the fertilization calcium wave.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcium ionophore A23187 induces expression of glucose-regulated genes and their heterologous fusion genes

1985 ◽  
Vol 5 (6) ◽  
pp. 1212-1219
Author(s):  
E Resendez ◽  
J W Attenello ◽  
A Grafsky ◽  
C S Chang ◽  
A S Lee
Keyword(s):  
Gene Transfection ◽  
Calcium Ionophore ◽  
Fold Increase ◽  
Calcium Ionophore A23187 ◽  
Induced Response ◽  
Specific Gene ◽  
Regulatory Sequence ◽  
Cdna Clones ◽  
Ionophore A23187 ◽  
Flanking Sequence

Using two cDNA clones which encode hamster genes specifically induced by glucose starvation, we demonstrated that an 8- and 30-fold increase, respectively, in the transcription rates of these genes was coordinately effected by calcium ionophore A23187 treatment, resulting in a similar increase in the steady-state levels of their mRNAs. This response was observed within several hours of ionophore treatment in several mammalian cell types and appeared to be specifically mediated by A23187 but not by other ionophores in general. To define the regulatory sequence which mediates this Ca2+-induced response, we showed by gene transfection techniques that the 5' flanking sequence of a rat glucose-regulated gene contained the region for induction by A23187. The system reported here offers attractive features for the study of specific gene regulation by Ca2+.

Cell cycle progression of parthenogenetically activated mouse oocytes to interphase is dependent on the level of internal calcium

1992 ◽  
Vol 103 (2) ◽  
pp. 389-396 ◽  
Author(s):  
C. Vincent ◽  
T.R. Cheek ◽  
M.H. Johnson
Keyword(s):  
Cell Cycle Progression ◽  
Polar Body ◽  
Calcium Ionophore ◽  
Cytosolic Calcium ◽  
Calcium Ionophore A23187 ◽  
Mouse Oocyte ◽  
Free Calcium ◽  
Ionophore A23187 ◽  
Parthenogenetic Activation ◽  
Mouse Oocytes

Nuclear maturation of the mouse oocyte becomes arrested in metaphase of the second meiotic division (MII). Fertilization or parthenogenetic activation induces meiotic completion, chromosomal decondensation and formation of a pronucleus. This completion of meiosis is probably triggered by a transient increase in cytosolic calcium ions. When activated just after ovulation by a low concentration of the calcium ionophore A23187, the majority of the mouse oocytes go through a metaphase to anaphase transition and extrude their second polar body but they do not proceed into interphase; instead their chromatids remain condensed and a microtubular metaphase spindle reforms (metaphase III). However, a high percentage of these oocytes will undergo a true parthenogenetic activation assessed by the formation of a pronucleus, when exposed to a higher concentration of the calcium ionophore. The capacity of the mouse oocyte to pass into metaphase III is lost with increasing time post-ovulation. Direct measurement of intracellular calcium with Fura-2 reveals higher levels of cytosolic calcium in aged oocytes and/or using higher concentrations of calcium ionophore for activation. It is concluded that the internal free calcium level determines the transition to interphase.

Amplification of LTB4 generation in AM-PMN cocultures: transcellular 5-lipoxygenase metabolism

1991 ◽  
Vol 261 (2) ◽  
pp. L195-L203 ◽  
Author(s):  
F. Grimminger ◽  
U. Sibelius ◽  
W. Seeger
Keyword(s):  
Hydrolysis Product ◽  
Calcium Ionophore ◽  
Fold Increase ◽  
Metabolite Profile ◽  
Product Formation ◽  
Calcium Ionophore A23187 ◽  
Oxidation Products ◽  
Ionophore A23187 ◽  
Lipoxygenase Product ◽  
Isolated Cell

The generation of arachidonic acid (AA) metabolites by human polymorphonuclear leukocytes (PMN) and by rabbit alveolar macrophages (AM) was investigated and compared with that produced under conditions of coculture. Incubation of PMN with the calcium ionophore A23187 resulted in rapid generation of leukotriene (LT) B4 and its omega-oxidation products, paralleled by substantial secretion of 5-hydroxyeicosatetraenoic acid (HETE) and intact LTA4. Rapid LTA4 decay to nonenzymatic hydrolysis products in the extracellular space ensued. Exogenous AA, offered simultaneously with the ionophore, markedly increased 5-lipoxygenase product formation. Incubation of AM with A23187 evoked protracted generation of LTB4 in the absence of omega-oxidation, with concomitant liberation of 5-HETE, 15-HETE, free AA, and minor amounts of AA cyclooxygenase products. Exogenously offered LTA4 was avidly taken up and converted into LTB4 by these cells. Costimulation of AM and PMN with the ionophore resulted in an approximately 2.5-fold increase in the generation of LTB4 and its metabolites (compared with the summed amounts of the isolated cell experiments), whereas 5-HETE and nonenzymatic LTA4, hydrolysis product formation were markedly reduced. This change in metabolite profile was dependent on the AM-to-PMN ratio. Acetylsalicylic acid increased 5-lipoxygenase product formation in the coculture studies but not in the isolated cell experiments. AA prelabeling of either PMN or AM resulted in radioactivity detection in all AA lipoxygenase products except for 15-HETE.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Is a rise in intracellular concentration of free calcium necessary or sufficient for stimulated cytoskeletal-associated actin?

1986 ◽  
Vol 102 (4) ◽  
pp. 1459-1463 ◽  
Author(s):  
R I Sha'afi ◽  
J Shefcyk ◽  
R Yassin ◽  
T F Molski ◽  
M Volpi ◽  
...  
Keyword(s):  
Intracellular Calcium ◽  
Pertussis Toxin ◽  
Incubation Medium ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Extracellular Calcium ◽  
Intracellular Concentration ◽  
The Other ◽  
Free Calcium ◽  
Ionophore A23187

The addition of the calcium ionophore A23187 to rabbit neutrophils increases the amount of actin associated with the cytoskeleton regardless of the presence or absence of calcium in the incubation medium. In the presence of extracellular calcium, the effect of A23187 is biphasic with respect to concentration. The action of the ionophore is rapid, transient, and is inhibited by pertussis toxin, hyperosmolarity, and quinacrine. On the other hand, the addition of pertussis toxin or hyperosmolarity has small if any, effect on the rise in intracellular calcium produced by A23187. While quinacrine does not affect the fMet-Leu-Phe-induced increase in cytoskeletal actin and the polyphosphoinositide turnover, its addition inhibits completely the stimulated increase in Ca-influx produced by the same stimulus. The results presented here suggest that a rise in the intracellular concentration of free calcium is neither necessary nor sufficient for the stimulated increase in cytoskeletal-associated actin. A possible relationship between the lipid remodeling stimulated by chemoattractants and the increased cytoskeletal actin is discussed.

scholarly journals Calcium uptake and release by isolated cortices and microsomes from the unfertilized egg of the sea urchin Strongylocentrotus droebachiensis.

1986 ◽  
Vol 102 (6) ◽  
pp. 2205-2210 ◽  
Author(s):  
J A Oberdorf ◽  
J F Head ◽  
B Kaminer
Keyword(s):  
Sea Urchin ◽  
Calcium Uptake ◽  
Inositol Trisphosphate ◽  
Calcium Ionophore ◽  
Strongylocentrotus Droebachiensis ◽  
Cortical Granule ◽  
Free Calcium ◽  
Cortical Region ◽  
Ionophore A23187 ◽  
Dependent Manner

Isolated cortices from unfertilized sea urchin eggs sequester calcium in an ATP-dependent manner when incubated in a medium containing free calcium levels characteristic of the resting cell (approximately 0.1 microM). This ATP-dependent calcium uptake activity was measured in the presence of 5 mM Na azide to prevent mitochondrial accumulation, was increased by oxalate, and was blocked by 150 microM quercetin and 50 microM vanadate (known inhibitors of calcium uptake into the sarcoplasmic reticulum). Cortical regions preloaded with 45Ca in the presence of ATP were shown to dramatically increase their rate of calcium efflux upon the addition of (a) the calcium ionophore A23187 (10 microM), (b) trifluoperazine (200 microM), (c) concentrations of free calcium that activated cortical granule exocytosis, and (d) the calcium mobilizing agent inositol trisphosphate. This pool of calcium is most likely sequestered in the portion of the egg's endoplasmic reticulum that remains associated with the cortical region during its isolation. We have developed a method for obtaining a high yield of purified microsomal vesicles from whole eggs. This preparation also demonstrates ATP-dependent calcium sequestering activity which increases in the presence of oxalate and has similar sensitivities to calcium transport inhibitors; however, the isolated microsomal vesicles did not show any detectable release of calcium when exposed to inositol trisphosphate.

The relationship between secretion and intracellular free calcium in bovine adrenal chromaffin cells

1984 ◽  
Vol 4 (7) ◽  
pp. 605-611 ◽  
Author(s):  
Robert D. Burgoyne
Keyword(s):  
Chromaffin Cells ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Catecholamine Release ◽  
Intracellular Free Calcium ◽  
Free Calcium ◽  
Ionophore A23187 ◽  
Adrenal Chromaffin Cells ◽  
Adrenal Chromaffin ◽  
The Relationship

The effect of carbamylcholine and the calcium ionophore A23187 on catecholamine release and intracellular free calcium, [Ca2+]i, in bovine adrenal chromaffin cells was determined. At 10−4M carbamylcholine maximal release occurred with an accompanying increase in [Ca2+]i from a basal level of 168 nM to less than 300 nM. An increase in [Ca2+]i of a similar magnitude was found following challenge with 40 nM A23187. However, in this case, no catecholamine release occurred. These results suggest that stimulation of secretion from chromaffin cells by carbamylcholine may involve additional triggers which stimulate secretion at low [Ca2+]i.

scholarly journals Interrelationships of polymorphonuclear neutrophil membrane-bound calcium, membrane potential, and chemiluminescence: studies in single living cells

Blood ◽  
1984 ◽  
Vol 64 (6) ◽  
pp. 1184-1192 ◽  
Author(s):  
GW Sullivan ◽  
GR Donowitz ◽  
JA Sullivan ◽  
GL Mandell
Keyword(s):  
Membrane Potential ◽  
Calcium Release ◽  
Calcium Ionophore ◽  
Image Intensifier ◽  
Calcium Ionophore A23187 ◽  
Polymorphonuclear Neutrophil ◽  
Human Neutrophils ◽  
Ionophore A23187 ◽  
Ionic Fluxes ◽  
Single Living

Abstract Stimulated neutrophils show ionic fluxes that may function as “transducers” between stimuli and effector functions. Using fluorescent probes, patterns of membrane-associated calcium (chlortetracycline, CTC) and membrane potential (3–3′-dipentyloxacarbocyanine, di-O-C5 (3)) in single living human neutrophils were observed with a fluorescence microscope fitted with an image intensifier and photometer. Fluorescence changes were related to chemiluminescence. In unstimulated neutrophils, CTC and di-O-C5 (3) fluorescence was brightest in the perinuclear region. Di-O-C5 (3) fluorescence was also seen in mitochondria. Neutrophil stimulation with zymosan, phorbol myristate acetate (PMA) or calcium ionophore (A23187) resulted in loss of di-O-C5 (3) and CTC fluorescence and chemiluminescence proportional to the strength of the stimulus. Experiments demonstrated the independence of these processes. (1) Digitonin stimulation caused chemiluminescence and di-O-C5 (3) darkening without loss of CTC fluorescence. (2) Depolarization of neutrophils did not induce CTC darkening or chemiluminescence. (3) Calcium ionophore (A23187) stimulation of neutrophils in calcium-free medium resulted in normal di-O-C5 (3) and CTC darkening, but a blunted chemiluminescence peak. (4) Calcium ionophore (A23187) stimulated the loss of di-O-C5 (3) and CTC fluorescence from chronic granulomatous disease neutrophils, but did not trigger an oxidative burst. Although neutrophil depolarization, calcium release from membranes, and oxidative activity are linked, these processes can clearly be separated.

The role of Src family kinases in starfish egg fertilisation

Zygote ◽  
1999 ◽  
Vol 8 (S1) ◽  
pp. S16-S17 ◽  
Author(s):  
Andrew F. Giusti ◽  
Kathy R. Foltz ◽  
Laurinda. A. Jaffe
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Kinase Inhibitors ◽  
Calcium Ionophore ◽  
Calcium Ionophore A23187 ◽  
Free Calcium ◽  
Ionophore A23187 ◽  
Tyrosine Kinase Activity ◽  
Sh2 Domains ◽  
Upstream Regulator

A common early feature in the activation of all eggs during fertilisation is an increase in the level of intra-cellular free calcium (Ca2+) that, in most species, propagates as a wave across the egg (reviewed in Strieker, 1999). In echinoderms, this Ca2+ release is the result of a signal transduction cascade that requires phospholipase Cγ (PLCγ)-mediated production of inositol trisphosphate (IP3) (Carroll et al., 1997, 1999). PLCγ is most commonly regulated by tyrosine phosphorylation (Rhee & Bae, 1997), indicating that a tyrosine kinase is a likely upstream regulator of PLCγ enzymatic activity at fertilisation. In support of this hypothesis, an increase in tyrosine kinase activity and an increase in tyrosine-phosphorylated proteins at fertilisation has been observed in echinoderm eggs (Satoh & Garbers, 1985; Ciapa & Epel, 1991; Kinsey, 1997). Moreover, the tyrosine kinase inhibitors genistein (Shen et al., 1999) and PP1 (Abassi et al., 2000) have been used to show that in sea urchin eggs a tyrosine kinase activity is required for normal Ca2+ release in response to fertilisation.In eggs of the starfish Asterina miniata, a Src-type tyrosine kinase has been identified as a potential regulator of PLCγ activity at fertilisation (Giusti et al., 1999a). This kinase exhibits a rapid fertilisation-dependent association specifically with the Src Homology 2 (SH2) domains of PLCγ. Moreover, the timing of this association correlates with an increase in the tyrosine kinase activity bound to the PLCγ SH2 domains, and neither the Src kinase nor the associated kinase activity was observed to associate with the PLCγ SH2 domains after treating eggs with the calcium ionophore A23187 (Giusti et al., 1999a). These data identify an egg Src family kinase as a potential upstream regulator of PLCγ during starfish egg fertilisation.

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