Click
here to close Hello! We notice that
you are using Internet Explorer, which is not supported by Echinobase
and may cause the site to display incorrectly. We suggest using a
current version of Chrome,
FireFox,
or Safari.
PLoS One
2013 Jan 01;86:e66113. doi: 10.1371/journal.pone.0066113.
Show Gene links
Show Anatomy links
Intracellular and extracellular pH and Ca are bound to control mitosis in the early sea urchin embryo via ERK and MPF activities.
Ciapa B, Philippe L.
???displayArticle.abstract???
Studies aiming to predict the impact on marine life of ocean acidification and of altered salinity have shown altered development in various species including sea urchins. We have analyzed how external Na, Ca, pH and bicarbonate control the first mitotic divisions of sea urchin embryos. Intracellular free Ca (Cai) and pH (pHi) and the activities of the MAP kinase ERK and of MPF regulate mitosis in various types of cells including oocytes and early embryos. We found that intracellular acidification of fertilized eggs by Na-acetate induces a huge activation of ERK at time of mitosis. This also stops the cell cycle and leads to cell death, which can be bypassed by treatment with the MEK inhibitor U0126. Similar intracellular acidification induced in external medium containing low sodium or 5-(N-Methyl-N-isobutyl) amiloride, an inhibitor of the Na(+)/H(+) exchanger, also stops the cell cycle and leads to cell death. In that case, an increase in Cai and in the phosphorylation of tyr-cdc2 occurs during mitosis, modifications that depend on external Ca. Our results indicate that the levels of pHi and Cai determine accurate levels of Ptyr-Cdc2 and P-ERK capable of ensuring progression through the first mitotic cycles. These intracellular parameters rely on external Ca, Na and bicarbonate, alterations of which during climate changes could act synergistically to perturb the early marine life.
???displayArticle.pubmedLink???
23785474 ???displayArticle.pmcLink???PMC3681939 ???displayArticle.link???PLoS One
Figure 1. ERK and CDK activities control Cai and pHi after fertilization.A. Time courses of Cai changes after fertilization in eggs treated or not (a) 10 mins after sperm addition (time zero) with 2 µM U0126 (b) or 20 µM Roscovitine (c). One typical recording is shown for each condition. Cai transients occur at time of pronuclear migration (black arrows) and at mitosis (grey arrow). Inset images taken 80 mins after fertilization show normal division in control eggs (a), mitotic alterations with U0126 (b) and absence of mitosis with Roscovitine (c). B. Time course of pHi changes after fertilization of control eggs. C. Relative changes in pHi (a) and Cai (b) levels in eggs treated or not (control) with 2 µM U0126 or 20 µM Roscovitine. The mean levels of pHi recorded from 60 and 65 mins following sperm addition are expressed relative to that of unfertilized egg (arbitrarily taken as 1). Mean levels of Cai recorded during 5 mins at time of the mitotic peak (grey arrow and line in Fig. A), i.e. between 35–40 mins in control eggs, 30–35 mins in U0126 and 25–30 mins in Roscovitine treated eggs, are expressed as the percentage of the fertilization Cai peak arbitrarily taken as 100. The total number of eggs monitored is indicated for each condition (brackets). Values (mean +/− sem) are significantly higher than that of control eggs (**, student test, p<0.01) or not significantly different (ns).
Figure 2. Changes in Cai and pHi during mitosis depend on external Ca++ and Na+.Eggs were transferred in the different media after fertilization (arrow). Two examples representative of n measurements (number in brackets) are shown in each condition. Variations in pHi (a), evolution of Cai (b) and images of eggs taken 70 min after fertilization (insets in a). A. Transfer in 0Na (1), Am (2) or Ac (3). B. Effect of additional absence of external Ca after transfer in 0Na0Ca (1), Am0Ca (2) or Ac0Ca (3). C. Mean levels of pHi (a) and Cai (b) changes recorded from 60–65 mins after sperm addition in Figs. A and B. pHi changes (a) are expressed relative to that of unfertilized egg (arbitrarily taken as 1) while Cai changes (b) are expressed as the percentage of the fertilization Cai peak arbitrarily taken as 100 (zero is the unfertilized level). Values (means +/− sem) obtained in the absence of external Ca are significantly different (student test, p<0.01, two black stars) or not (ns, black letters) from control. Values obtained in the absence of Ca are significantly different (p<0.01, two grey stars) or not (ns, grey letters) from those obtained in the presence of Ca. Number of eggs is indicated for each condition (brackets).
Figure 4. P-ERK activity controls mitosis and survival of fertilized eggs.A. Images taken 3 hours after fertilization of eggs transferred or not (control) 25 mins after fertilization in Ac containing or not 2 µM U0126. B. The experiment shown in A was performed three times and the data obtained pooled. Eggs were also transferred in 0Na or Am. % of divided eggs (a), embryos (b) or fragmented eggs (c) were determined 3 hours after fertilization (filled histograms) except for divided control eggs that were counted 80 mins after sperm addition (hatched histograms). 42–78 total embryos were counted in each condition. Values (means +/− sem) obtained in the presence of U0126 (grey histogram) are significantly different (student test, p<0.01, two stars) or not (ns) to those obtained without this drug (black histogram).
Figure 5. Cai and pHi depend on the presence of external HCO3–.A. Observation 80 mins after fertilization. Eggs develop in ASW (Control) or are transferred 20 mins after fertilization into ASW deprived of Ca (0Ca), HCO3
− (0HCO3) or of Na+ and Ca++ (0Na0Ca). B. Time course after fertilization of pHi (a) and Cai (b) in ASW, 0Na and 0Na0Ca in the presence or not of HCO3
−. Examples of results obtained in absence of HCO3-, i.e. in 0HCO3 (1), 0Na0HCO3 (2) and 0Na0Ca0HC03 (3), are depicted in different grey colours and representative of n determinations (grey number in brackets). In each condition, one typical control experiment performed with the same population of eggs in the presence of HCO3
−, i.e. in ASW (1), 0Na (2) and 0Na0Ca (3) is shown in black curve and representative of n determinations (black number in brackets).
Figure 6. Na/Ca inhibitors reduce inhibition of mitosis induced in the absence of external Na.Eggs were let to develop in ASW (Control) or transferred 20 min after fertilization in 0Na containing or not (0Na) the different inhibitors, BHC, SN6 or KB. Observation 80 min after fertilization (A) and compiled assessment of results (means +/− sem) from 3 experiments that gave similar results (B). Total number of eggs counted in each condition is indicated in brackets in B.
Amirand,
Intracellular pH in one-cell mouse embryo differs between subcellular compartments and between interphase and mitosis.
2000, Pubmed
Amirand,
Intracellular pH in one-cell mouse embryo differs between subcellular compartments and between interphase and mitosis.
2000,
Pubmed Arion,
M-phase-specific protein kinase from mitotic sea urchin eggs: cyclic activation depends on protein synthesis and phosphorylation but does not require DNA or RNA synthesis.
1989,
Pubmed
,
Echinobase Berridge,
Inositol trisphosphate and calcium signalling mechanisms.
2009,
Pubmed Carballeira,
Influence of salinity on fertilization and larval development toxicity tests with two species of sea urchin.
2011,
Pubmed
,
Echinobase Casey,
Sensors and regulators of intracellular pH.
2010,
Pubmed Chiri,
Evidence for MAP kinase activation during mitotic division.
1998,
Pubmed
,
Echinobase Davies,
Specificity and mechanism of action of some commonly used protein kinase inhibitors.
2000,
Pubmed Edgecombe,
A cyclin-abundance cycle-independent p34cdc2 tyrosine phosphorylation cycle in early sea urchin embryos.
1991,
Pubmed
,
Echinobase Epel,
Mechanisms of activation of sperm and egg during fertilization of sea urchin gametes.
1978,
Pubmed
,
Echinobase Frémin,
Multiple division cycles and long-term survival of hepatocytes are distinctly regulated by extracellular signal-regulated kinases ERK1 and ERK2.
2009,
Pubmed Grainger,
Intracellular pH controls protein synthesis rate in the sea urchine egg and early embryo.
1979,
Pubmed
,
Echinobase Grynkiewicz,
A new generation of Ca2+ indicators with greatly improved fluorescence properties.
1985,
Pubmed Haccard,
Induction of metaphase arrest in cleaving Xenopus embryos by MAP kinase.
1993,
Pubmed Hamaguchi,
Measurement of the intracellular pH threshold for sperm aster formation in sea urchin eggs.
2001,
Pubmed
,
Echinobase Hara,
Start of the embryonic cell cycle is dually locked in unfertilized starfish eggs.
2009,
Pubmed
,
Echinobase Harrison,
Muscarinic signalling affects intracellular calcium concentration during the first cell cycle of sea urchin embryos.
2002,
Pubmed
,
Echinobase Huang,
Differentiation impairs low pH-induced Ca2+ signaling and ERK phosphorylation in granule precursor tumour cells.
2009,
Pubmed Iwamoto,
Forefront of Na+/Ca2+ exchanger studies: molecular pharmacology of Na+/Ca2+ exchange inhibitors.
2004,
Pubmed Johnson,
Intracellular pH of sea urchin eggs measured by the dimethyloxazolidinedione (DMO) method.
1981,
Pubmed
,
Echinobase Kishimoto,
Cell-cycle control during meiotic maturation.
2003,
Pubmed Kleyman,
Amiloride and its analogs as tools in the study of ion transport.
1988,
Pubmed Kumano,
Calcium-mediated inactivation of the MAP kinase pathway in sea urchin eggs at fertilization.
2001,
Pubmed
,
Echinobase Liu,
The physiology of bicarbonate transporters in mammalian reproduction.
2012,
Pubmed Lopo,
The rise and fall of intracellular pH of sea urchin eggs after fertilisation.
1977,
Pubmed
,
Echinobase Machaca,
Ca2+ signaling differentiation during oocyte maturation.
2007,
Pubmed Malo,
Physiological role and regulation of the Na+/H+ exchanger.
2006,
Pubmed Martin,
Early development and molecular plasticity in the Mediterranean sea urchin Paracentrotus lividus exposed to CO2-driven acidification.
2011,
Pubmed
,
Echinobase McCarty,
Manipulating tumor acidification as a cancer treatment strategy.
2010,
Pubmed Mukai,
Effects of extracellular acidic-alkaline stresses on trigeminal ganglion neurons in the mouse embryo in vivo.
2011,
Pubmed Murakami,
Analysis of the early embryonic cell cycles of Xenopus; regulation of cell cycle length by Xe-wee1 and Mos.
1998,
Pubmed Patel,
Calcium/calmodulin-dependent phosphorylation and activation of human Cdc25-C at the G2/M phase transition in HeLa cells.
1999,
Pubmed Payan,
Mechanisms regulating intracellular pH in sea urchin eggs.
1983,
Pubmed
,
Echinobase Philipova,
Inhibiting MAP kinase activity prevents calcium transients and mitosis entry in early sea urchin embryos.
2005,
Pubmed
,
Echinobase Place,
Effects of seawater acidification on cell cycle control mechanisms in Strongylocentrotus purpuratus embryos.
2012,
Pubmed
,
Echinobase Putney,
Na-H exchange-dependent increase in intracellular pH times G2/M entry and transition.
2003,
Pubmed Rees,
Protein synthesis increases after fertilization of sea urchin eggs in the absence of an increase in intracellular pH.
1995,
Pubmed
,
Echinobase Roderick,
Ca2+ signalling checkpoints in cancer: remodelling Ca2+ for cancer cell proliferation and survival.
2008,
Pubmed Ruknudin,
The regulation of the Na/Ca exchanger and plasmalemmal Ca2+ ATPase by other proteins.
2007,
Pubmed Santo-Domingo,
The plasma membrane Na+/Ca2+ exchange inhibitor KB-R7943 is also a potent inhibitor of the mitochondrial Ca2+ uniporter.
2007,
Pubmed Sato,
Bepridil, an antiarrhythmic drug, opens mitochondrial KATP channels, blocks sarcolemmal KATP channels, and confers cardioprotection.
2006,
Pubmed Schreiber,
Ca2+ signaling, intracellular pH and cell volume in cell proliferation.
2005,
Pubmed Shaul,
The MEK/ERK cascade: from signaling specificity to diverse functions.
2007,
Pubmed Soliman,
Intracellular calcium signals regulate growth of hepatic stellate cells via specific effects on cell cycle progression.
2009,
Pubmed Stumpp,
Acidified seawater impacts sea urchin larvae pH regulatory systems relevant for calcification.
2012,
Pubmed
,
Echinobase Sunda,
Eutrophication induced CO₂-acidification of subsurface coastal waters: interactive effects of temperature, salinity, and atmospheric PCO₂.
2012,
Pubmed Suprynowicz,
Fluctuation of the Ca-sequestering activity of permeabilized sea urchin embryos during the cell cycle.
1985,
Pubmed
,
Echinobase Toyoshima,
How Ca2+-ATPase pumps ions across the sarcoplasmic reticulum membrane.
2009,
Pubmed Tseng,
Matriptase activation, an early cellular response to acidosis.
2010,
Pubmed Uhlén,
Biochemistry of calcium oscillations.
2010,
Pubmed Vaughan-Jones,
Intracellular pH regulation in heart.
2009,
Pubmed Whitaker,
Calcium microdomains and cell cycle control.
2006,
Pubmed Wilding,
Local perinuclear calcium signals associated with mitosis-entry in early sea urchin embryos.
1996,
Pubmed
,
Echinobase Wu,
Across the meiotic divide - CSF activity in the post-Emi2/XErp1 era.
2008,
Pubmed Yue,
Mos mediates the mitotic activation of p42 MAPK in Xenopus egg extracts.
2004,
Pubmed Zhang,
Inactivation of MAPK in mature oocytes triggers progression into mitosis via a Ca2+ -dependent pathway but without completion of S phase.
2006,
Pubmed
,
Echinobase Zhang,
A MAPK pathway is involved in the control of mitosis after fertilization of the sea urchin egg.
2005,
Pubmed
,
Echinobase Zorec,
Simultaneous measurements of cytosolic pH and calcium interactions in bovine lactotrophs using optical probes and four-wavelength quantitative video microscopy.
1993,
Pubmed
