Involvement of inositol 1,4,5-trisphosphate-mediated Ca2+ release in early and late events of mouse egg activation

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1851-1859 ◽  
Author(s):  
Z. Xu ◽  
G.S. Kopf ◽  
R.M. Schultz
Keyword(s):  
Inhibitory Effect ◽  
Egg Activation ◽  
Dependent Manner ◽  
Ip3 Receptor ◽  
Concentration Dependent Manner ◽  
Post Translational Modifications ◽  
Inositol 1,4,5 Trisphosphate ◽  
Mammalian Eggs ◽  
Mouse Egg

Sperm-induced activation of mammalian eggs is associated with a transient increase in the concentration of intracellular Ca2+. The role of inositol 1,4,5-trisphosphate (IP3)-mediated release of Ca2+ from intracellular stores during mouse egg activation was examined in the present study by determining the effects of microinjected monoclonal antibody (mAb) 18A10, which binds to the IP3 receptor and inhibits IP3-induced Ca2+ release, on endpoints of egg activation following insemination. The antibody inhibited in a concentration-dependent manner the ZP2 to ZP2f conversion that is involved in the zona pellucida block to polyspermy, as well as the ZP2 to ZP2f conversion promoted by microinjected IP3 in non-inseminated eggs. As anticipated, inseminated eggs that had been microinjected with the antibody were polyspermic. In addition, the antibody inhibited the fertilization-associated decrease in H1 kinase activity and pronucleus formation, and the concentration dependence for inhibition of these events was similar to that observed for inhibiting the ZP2 to ZP2f conversion. Last, the antibody inhibited the fertilization-induced recruitment of maternal mRNAs and post-translational modifications of proteins. In each case, eggs microinjected with the mAb 4C11, which also binds to the IP3 receptor but does not inhibit IP3-induced Ca2+ release, had no inhibitory effect on fertilization and egg activation. Results of these studies suggest that IP3-mediated Ca2+ release is essential for both early and late events of mouse egg activation.

Regulation of mouse egg activation: presence of ryanodine receptors and effects of microinjected ryanodine and cyclic ADP ribose on uninseminated and inseminated eggs

Development ◽  
1995 ◽  
Vol 121 (7) ◽  
pp. 2233-2244 ◽  
Author(s):  
T. Ayabe ◽  
G.S. Kopf ◽  
R.M. Schultz
Keyword(s):  
Ryanodine Receptor ◽  
Ryanodine Receptors ◽  
Meiotic Spindle ◽  
Egg Activation ◽  
Dependent Manner ◽  
Cyclic Adp Ribose ◽  
Inositol 1,4,5 Trisphosphate ◽  
Mouse Egg

Sperm-induced activation of mammalian eggs is associated with a transient increase in Ca2+ concentrations thought to be derived from inositol 1,4,5-trisphosphate-sensitive and -insensitive intracellular stores. Whereas the importance of inositol 1,4,5-trisphosphate-sensitive Ca2+ stores has been evaluated, the identity and role of inositol 1,4,5-trisphosphate-insensitive stores are poorly understood. To explore the role of the ryanodine-sensitive Ca2+ store, we first used reverse transcription-polymerase chain reaction to identify transcripts of the ryanodine receptor in eggs and determined that transcripts for the type 2 and 3 receptor were present. Immunoprecipitation of radioiodinated egg extracts with an antibody that recognizes both type 2 and 3 receptors detected specifically a band of Mr = 520,000. Immunolocalization of the receptor(s) using laser-scanning confocal microscopy revealed that the receptor(s) was uniformly distributed in the cortex of the germinal vesicle-intact oocyte, but became asymmetrically localized to the cortex in a region apposed to the meiotic spindle in the metaphase II-arrested egg; this asymmetrical localization developed by metaphase I. The role of the ryanodine receptor in mouse egg activation was examined by determining the effects of microinjected ryanodine or cyclic ADP ribose on endpoints of egg activation in either uninseminated or inseminated eggs. Ryanodine induced the conversion of the zona pellucida glycoprotein ZP2 to its postfertilization form ZP2f in a biphasic concentration-dependent manner; nanomolar concentrations stimulated this conversion, whereas micromolar concentrations had no stimulatory effect. Cyclic ADP ribose also promoted the ZP2 conversion, but with a hyperbolic concentration dependence. Neither of these compounds induced cell cycle resumption. Inhibiting the inositol 1,4,5-trisphosphate-sensitive Ca2+ store did not inhibit the ryanodine-induced ZP2 conversion and, reciprocally, inhibiting the ryanodine-sensitive Ca2+ store did not inhibit the inositol 1,4,5-trisphosphate-induced ZP2 conversion. Last, treatment of eggs under conditions that would block the release of Ca2+ from the ryanodine-sensitive store had no effect on any event of egg activation following fertilization. Results of these experiments suggest that although ryanodine receptors are present and functional, release of Ca2+ from this store is not essential for sperm-induced egg activation.

Permeability of endothelial monolayers to albumin is increased by bradykinin and inhibited by prostaglandins

2001 ◽  
Vol 280 (4) ◽  
pp. L732-L738 ◽  
Author(s):  
Pierre J. Farmer ◽  
Sylvie G. Bernier ◽  
Andrée Lepage ◽  
Gaétan Guillemette ◽  
Domenico Regoli ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Adenylate Cyclase ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Intracellular Level ◽  
Concentration Dependent Manner ◽  
Aortic Endothelial Cells ◽  
Endothelial Monolayers ◽  
Bovine Aortic Endothelial Cells

Using monolayers of bovine aortic endothelial cells (BAEC) in modified Boyden chambers, we examined the role of prostaglandins (PGs) in the bradykinin (BK)-induced increase of albumin permeability. BK induced a concentration-dependent increase of the permeability of BAEC, which reached 49.9 ± 1% at the concentration of 10−8 M. Two inhibitors of the prostaglandin G/H synthase, indomethacin (2.88 μM) and ibuprofen (10 μM), potentiated BK-induced permeability 1.8- and 3.9-fold, respectively. Exogenously administered PGE2and iloprost, a stable analog of prostacyclin, attenuated the effect of BK in a concentration-dependent manner. Butaprost equally reduced the effect of BK, suggesting the participation of the EP2receptor in this phenomenon. However, the EP4-selective antagonist AH-23848 did not significantly inhibit the protective effect of PGE2. The inhibitory effect of PGE2 was reversed by the adenylate cyclase inhibitor MDL-12330A (10 μM). These results suggest that BK-induced increase of permeability of BAEC monolayer to 125I-labeled albumin is negatively regulated by PGs. This postulated autocrine activity of PGs may involve an increase in the intracellular level of cAMP.

scholarly journals Inhibition of Ca2+ release from Trypanosoma brucei acidocalcisomes by 3,5-dibutyl-4-hydroxytoluene: role of the Na+/H+ exchanger

1997 ◽  
Vol 328 (2) ◽  
pp. 479-482 ◽  
Author(s):  
E. Anibal VERCESI ◽  
T. Mercedes GRIJALBA ◽  
Roberto DOCAMPO
Keyword(s):  
Trypanosoma Brucei ◽  
Antioxidant Properties ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Considerable Fraction ◽  
Preincubation Time

Acidocalcisomes are acidic vacuoles present in trypanosomatids that contain a considerable fraction of intracellular Ca2+. They possess a vacuolar-type H+-ATPase for H+ uptake, a Ca2+/H+ countertransporting ATPase for Ca2+ uptake and a Ca2+/nH+ antiporter for Ca2+ release. Trypanosoma brucei procyclic trypomastigotes acidocalcisomes possess, in addition, an Na+/H+ antiporter that may participate in Ca2+ release from these organelles. In this work we show that the hydrophobic antioxidant 3,5-dibutyl-4-hydroxy toluene (BHT), at concentrations in the range 1-20 μM, inhibits Na+-induced Ca2+ release from the acidocalcisomes of digitonin-permeabilized procyclic trypomastigotes in a concentration-dependent manner. This effect supports the notion that Ca2+ release from this compartment is regulated by the activity of the Na+/H+ antiporter. In the presence of BHT, Ca2+ release could still be obtained by nigericin-mediated alkalinization of the acidocalcisomes, clearly demonstrating that the action of BHT is not at the level of the Ca2+/nH+ antiporter but on that of the Na+/H+ antiporter. In the same range of concentrations and depending on the preincubation time, BHT had an stimulatory or an inhibitory effect on the vacuolar H+-ATPase present in T. brucei acidocalcisomes. Since these effects of BHT were obtained at concentrations which are commonly used for its antioxidant properties, these results indicate that care should be exercised when attributing effects of BHT to only these properties.

scholarly journals The cooperative activity between the carboxyl-terminal TSP1 repeats and the CUB domains of ADAMTS13 is crucial for recognition of von Willebrand factor under flow

Blood ◽  
2007 ◽  
Vol 110 (6) ◽  
pp. 1887-1894 ◽  
Author(s):  
Ping Zhang ◽  
Weilan Pan ◽  
Ann H. Rux ◽  
Bruce S. Sachais ◽  
X. Long Zheng
Keyword(s):  
Von Willebrand Factor ◽  
Dissociation Constants ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cooperative Activity ◽  
Carboxyl Terminal ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract ADAMTS13 cleaves von Willebrand factor (VWF) between Tyr1605 and Met1606 residues at the central A2 subunit. The amino-terminus of ADAMTS13 protease appears to be sufficient to bind and cleave VWF under static and denatured condition. However, the role of the carboxyl-terminus of ADAMTS13 in substrate recognition remains controversial. Present study demonstrates that ADAMTS13 cleaves VWF in a rotation speed– and protease concentration–dependent manner on a mini vortexer. Removal of the CUB domains (delCUB) or truncation after the spacer domain (MDTCS) significantly impairs its ability to cleave VWF under the same condition. ADAMTS13 and delCUB (but not MDTCS) bind VWF under flow with dissociation constants (KD) of about 50 nM and about 274 nM, respectively. The isolated CUB domains are neither sufficient to bind VWF detectably nor capable of inhibiting proteolytic cleavage of VWF by ADAMTS13 under flow. Addition of the TSP1 5-8 (T5-8CUB) or TSP1 2-8 repeats (T2-8CUB) to the CUB domains restores the binding affinity toward VWF and the inhibitory effect on cleavage of VWF by ADAMTS13 under flow. These data demonstrate directly and quantitatively that the cooperative activity between the middle carboxyl-terminal TSP1 repeats and the distal carboxyl-terminal CUB domains may be crucial for recognition and cleavage of VWF under flow.

scholarly journals cGMP decreases surface NKCC2 levels in the thick ascending limb: role of phosphodiesterase 2 (PDE2)

2008 ◽  
Vol 295 (4) ◽  
pp. F877-F887 ◽  
Author(s):  
Gustavo R. Ares ◽  
Paulo Caceres ◽  
Francisco J. Alvarez-Leefmans ◽  
Pablo A. Ortiz
Keyword(s):  
Inhibitory Effect ◽  
Thick Ascending Limb ◽  
Apical Surface ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Nacl Absorption ◽  
Medullary Thick Ascending Limb ◽  
P 75 ◽  
Cgmp Analog

NaCl absorption in the medullary thick ascending limb of the loop of Henle (THAL) is mediated by the apical Na/K/2Cl cotransporter (NKCC2). Hormones that increase cGMP, such as nitric oxide (NO) and natriuretic peptides, decrease NaCl absorption by the THAL. However, the mechanism by which cGMP decreases NaCl absorption in THALs is not known. We hypothesized that cGMP decreases surface NKCC2 levels in the THAL. We used surface biotinylation to measure surface NKCC2 levels in rat THAL suspensions. We tested the effect of the membrane-permeant cGMP analog dibutyryl-cGMP (db-cGMP) on surface NKCC2 levels. Incubating THALs with db-cGMP for 20 min decreased surface NKCC2 levels in a concentration-dependent manner (basal = 100%; db-cGMP 100 μM = 77 ± 7%; 500 μM = 54 ± 10% and 1,000 μM = 61 ± 8%). A different cGMP analog 8-bromo-cGMP (8-Br-cGMP) also decreased surface NKCC2 levels by 25%, (basal = 100%; 8-Br-cGM P = 75 ± 5%). Incubation of isolated, perfused THALs with db-cGMP decreased apical surface NKCC2 labeling levels as measured by immunofluorescence and confocal microscopy. cGMP-stimulated phosphodiesterase 2 (PDE2) mediates the inhibitory effect of NO on NaCl absorption by THALs. Thus we examined the role of PDE2 and found that PDE2 inhibitors blocked the effect of db-cGMP on surface NKCC2. Also, a nonstimulatory concentration of db-cAMP blocked the cGMP-induced decrease in surface NKCC2. Finally, db-cGMP inhibited THAL net Cl absorption by 48 ± 4%, and this effect was completely blocked by PDE2 inhibition. We conclude that cGMP decreases NKCC2 levels in the apical membrane of THALs and that this effect is mediated by PDE2. This is an important mechanism by which cGMP inhibits NaCl absorption by the THAL.

scholarly journals Brassinolide Enhances the Level of Brassinosteroids, Protein, Pigments, and Monosaccharides in Wolffia arrhiza Treated with Brassinazole

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1311
Author(s):  
Magdalena Chmur ◽  
Andrzej Bajguz
Keyword(s):  
Plant Growth ◽  
Growth And Development ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Plant Growth And Development ◽  
Concentration Dependent Manner ◽  
Spectrophotometric Methods ◽  
Synthetic Inhibitor ◽  
Wolffia Arrhiza ◽  
First Time

Brassinolide (BL) represents brassinosteroids (BRs)—a group of phytohormones that are essential for plant growth and development. Brassinazole (Brz) is as a synthetic inhibitor of BRs’ biosynthesis. In the present study, the responses of Wolffia arrhiza to the treatment with BL, Brz, and the combination of BL with Brz were analyzed. The analysis of BRs and Brz was performed using LC-MS/MS. The photosynthetic pigments (chlorophylls, carotenes, and xanthophylls) levels were determined using HPLC, but protein and monosaccharides level using spectrophotometric methods. The obtained results indicated that BL and Brz influence W. arrhiza cultures in a concentration-dependent manner. The most stimulatory effects on the growth, level of BRs (BL, 24-epibrassinolide, 28-homobrassinolide, 28-norbrassinolide, catasterone, castasterone, 24-epicastasterone, typhasterol, and 6-deoxytyphasterol), and the content of pigments, protein, and monosaccharides, were observed in plants treated with 0.1 µM BL. Whereas the application of 1 µM and 10 µM Brz caused a significant decrease in duckweed weight and level of targeted compounds. Application of BL caused the mitigation of the Brz inhibitory effect and enhanced the BR level in duckweed treated with Brz. The level of BRs was reported for the first time in duckweed treated with BL and/or Brz.

Adenosine A1 receptor-mediated inhibition of vasopressin action in inner medullary collecting duct

1994 ◽  
Vol 266 (5) ◽  
pp. F791-F796 ◽  
Author(s):  
R. M. Edwards ◽  
W. S. Spielman
Keyword(s):  
Receptor Agonist ◽  
Collecting Duct ◽  
Basolateral Membrane ◽  
Inhibitory Effect ◽  
Dependent Manner ◽  
Camp Accumulation ◽  
Concentration Dependent Manner ◽  
Cgs 21680 ◽  
Camp Generation ◽  
A1 Receptor

We examined the effects of adenosine and adenosine analogues on arginine vasopressin (AVP)-induced increases in osmotic water permeability (Pf; micron/s) and adenosine 3',5'-cyclic monophosphate (cAMP) accumulation in rat inner medullary collecting ducts (IMCDs). When added to the bath, the A1 receptor agonist N6-cyclohexyladenosine (CHA) produced a rapid and reversible inhibition of AVP-stimulated (10 pM) Pf (1,781 +/- 195 to 314 +/- 85 microns/s at 0.3 microM CHA; n = 9). The inhibitory effect of CHA was concentration dependent, with a 50% inhibitory concentration of 10 nM. The effect of CHA was inhibited by prior exposure of IMCDs to the A1 receptor antagonist 1,3-dipropylxanthine-8-cyclopentylxanthine (DP-CPX; 1 microM) or by preincubation with pertussis toxin. CHA had no effect on cAMP-induced increases in Pf. In addition to CHA, adenosine and the nonselective agonist 5'-(N-ethylcarboxamido)-adenosine (NECA) inhibited AVP-dependent Pf by > or = 70%, whereas the A2 receptor agonist CGS-21680 had no effect. Luminal adenosine (0.1 mM) had no effect on basal or AVP-stimulated Pf. CHA, NECA, and adenosine but not CGS-21680 inhibited AVP-stimulated cAMP accumulation in a concentration-dependent manner (50% inhibitory concentrations 0.1–300 nM). The inhibitory effect of CHA on AVP-stimulated cAMP accumulation was attenuated by DPCPX. We conclude that adenosine, acting at the basolateral membrane, inhibits AVP action in the IMCD via interaction with A1 receptors. The inhibition occurs proximal to cAMP generation and likely involves an inhibitory G protein.

Fibrinogen binding to the integrin αIIbβ3 modulates store-mediated calcium entry in human platelets

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2648-2656 ◽  
Author(s):  
Juan A. Rosado ◽  
Else M. Y. Meijer ◽  
Karly Hamulyak ◽  
Irena Novakova ◽  
Johan W. M. Heemskerk ◽  
...  
Keyword(s):  
Actin Cytoskeleton ◽  
Actin Polymerization ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Human Platelets ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Integrin Αiibβ3 ◽  
Fibrinogen Binding

Abstract Effects of the occupation of integrin αIIbβ3 by fibrinogen on Ca++signaling in fura-2–loaded human platelets were investigated. Adding fibrinogen to washed platelet suspensions inhibited increases in cytosolic [Ca++] concentrations ([Ca++]i) evoked by adenosine diphosphate (ADP) and thrombin in a concentration-dependent manner in the presence of external Ca++ but not in the absence of external Ca++ or in the presence of the nonselective cation channel blocker SKF96365, indicating selective inhibition of Ca++entry. Fibrinogen also inhibited store-mediated Ca++ entry (SMCE) activated after Ca++ store depletion using thapsigargin. The inhibitory effect of fibrinogen was reversed if fibrinogen binding to αIIbβ3 was blocked using RDGS or abciximab and was absent in platelets from patients homozygous for Glanzmann thrombasthenia. Fibrinogen was without effect on SMCE once activated. Activation of SMCE in platelets occurs through conformational coupling between the intracellular stores and the plasma membrane and requires remodeling of the actin cytoskeleton. Fibrinogen inhibited actin polymerization evoked by ADP or thapsigargin in control cells and in cells loaded with the Ca++ chelator dimethyl BAPTA. It also inhibited the translocation of the tyrosine kinase p60src to the cytoskeleton. These results indicate that the binding of fibrinogen to integrin αIIbβ3 inhibits the activation of SMCE in platelets by a mechanism that may involve modulation of the reorganization of the actin cytoskeleton and the cytoskeletal association of p60src. This action may be important in intrinsic negative feedback to prevent the further activation of platelets subjected to low-level stimuli in vivo.

The P-element-induced silencing effect of KP transposons is dose dependent in Drosophila melanogaster

Genome ◽  
2011 ◽  
Vol 54 (9) ◽  
pp. 752-762 ◽  
Author(s):  
Alireza Sameny ◽  
John Locke
Keyword(s):  
Drosophila Melanogaster ◽  
Critical Role ◽  
Mutagenic Effect ◽  
P Element ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
P Elements ◽  
Single Well ◽  
Dose Dependent

Transposable elements are found in the genomes of all eukaryotes and play a critical role in altering gene expression and genome organization. In Drosophila melanogaster, transposable P elements are responsible for the phenomenon of hybrid dysgenesis. KP elements, a deletion-derivative of the complete P element, can suppress this mutagenic effect. KP elements can also silence the expression of certain other P-element-mediated transgenes in a process called P-element-dependent silencing (PDS), which is thought to involve the recruitment of heterochromatin proteins. To explore the mechanism of this silencing, we have mobilized KP elements to create a series of strains that contain single, well-defined KP insertions that show PDS. To understand the quantitative role of KP elements in PDS, these single inserts were combined in a series of crosses to obtain genotypes with zero, one, or two KP elements, from which we could examine the effect of KP gene dose. The extent of PDS in these genotypes was shown to be dose dependent in a logarithmic rather than linear fashion. A logarithmic dose dependency is consistent with the KP products interacting with heterochromatic proteins in a concentration-dependent manner such that two molecules are needed to induce gene silencing.

Thrombin activatable fibrinolysis inhibitor (TAFI) affects fibrinolysis in a plasminogen activator concentration-dependent manner

2004 ◽  
Vol 91 (03) ◽  
pp. 473-479 ◽  
Author(s):  
Ana Guimarães ◽  
Dingeman Rijken
Keyword(s):  
Plasminogen Activator ◽  
In Vitro Study ◽  
Inhibitory Effect ◽  
Retardation Factor ◽  
Clot Lysis ◽  
Dependent Manner ◽  
Plasma Clot ◽  
Concentration Dependent Manner ◽  
Plasmin Inhibitor

SummaryTAFIa was shown to attenuate fibrinolysis. In our in vitro study, we investigated how the inhibitory effect of TAFIa depended on the type and concentration of the plasminogen activator (PA). We measured PA-mediated lysis times of plasma clots under conditions of maximal TAFI activation by thrombin-thrombomodulin in the absence and presence of potato carboxypeptidase inhibitor. Seven different PAs were compared comprising both tPA-related (tPA, TNK-tPA, DSPA), bacterial PA-related (staphylokinase and APSAC) and urokinase-related (tcu-PA and k2tu-PA) PAs. The lysis times and the retardation factor were plotted against the PA concentration. The retardation factor plots were bell-shaped. At low PA concentrations, the retardation factor was low, probably due to the limited stability of TAFIa. At intermediate PA concentrations the retardation factor was maximal (3-6 depending on the PA), with TNK-tPA, APSAC and DSPA exhibiting the strongest effect. At high PA concentrations, the retardation factor was again low, possibly due to inactivation of TAFIa by plasmin or to a complete conversion of glu-plasminogen into lys-plasminogen. Using individual plasmas with a reduced plasmin inhibitor activity (plasmin inhibitor Enschede) the bell-shaped curve of the retardation factor shifted towards lower tPA and DSPA concentrations, but the height did not decrease. In conclusion, TAFIa delays the lysis of plasma clots mediated by all the plasminogen activators tested. This delay is dependent on the type and concentration of the plasminogen activator, but not on the fibrin specificity of the plasminogen activator. Furthermore, plasmin inhibitor does not play a significant role in the inhibition of plasma clot lysis by TAFI.

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