Mechanisms regulating intracellular pH in sea urchin eggs

Payan, P.; Girard, Jean‐Pierre; Ciapa, Brigitte

doi:10.1016/0012-1606(83)90197-5

Cited by 66 publications

(42 citation statements)

References 23 publications

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“…Treatment of eggs with concentrations of PD98059 as high as 50 M did not trigger any increase in pH i and eggs behaved like untreated eggs. An increase of 0.35 pH units was, as expected, detected after fertilization (Payan et al, 1983) but was not altered by PD98059 (Fig. 5A).…”

Section: Entry Into Mitosis After Inactivation Of Mek Is Independent supporting

confidence: 84%

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Inactivation of MAPK in mature oocytes triggers progression into mitosis via a Ca2+-dependent pathway but without completion of S phase

Zhang

Huitorel

Genevière

et al. 2006

Journal of Cell Science

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Unfertilized sea urchin eggs that are arrested at G1 phase after completion of meiosis contain a highly phosphorylated mitogen-activated protein (MAP) kinase (MAPK), the ERK-like protein (ERK-LP). Several data including our previous results show that ERK-LP is inactivated after fertilization, which agrees with results obtained in other species including Xenopus, starfish and mammals. The question is to elucidate the function of a high MAPK activity in sea urchin eggs. We report here that dephosphorylation of ERK-LP with very low concentrations of two MEK inhibitors, PD98059 or U0126, triggers entry into mitosis. Under these conditions, recurrent oscillations of the phosphorylation of ERK-LP and of a tyrosine residue in Cdc2 occur, and the intracellular Ca2+ level (Ca2+i) progressively and slowly increases. Nuclear envelope breakdown and all mitotic events initiated after dephosphorylation of ERK-LP are inhibited when changes in Ca2+i are prevented; however, they are independent of the intracellular pH. These results suggest that inactivation of a MEK-ERK pathway, normally induced after fertilization of sea urchin eggs, triggers entry into mitosis by altering Ca2+i but cannot trigger full DNA replication. We discuss the hypothesis that neither inactivation nor activation of a MEK-ERK pathway is required for S phase completion in sea urchin egg.

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Section: Entry Into Mitosis After Inactivation Of Mek Is Independent supporting

confidence: 84%

“…Variations of pH i were measured following the protocol as previously described in detail (Payan et al, 1983).…”

Section: Determination Of Ph Imentioning

confidence: 99%

Inactivation of MAPK in mature oocytes triggers progression into mitosis via a Ca2+-dependent pathway but without completion of S phase

Zhang

Huitorel

Genevière

et al. 2006

Journal of Cell Science

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“…But additional water Dubé et al (1985) Paracentrotus lividus 7.38 7.64 DMO method Payan et al (1983) Strongylocentrotus purpuratus 7.08 7.47 DMO method Johnson and Epel (1981) 7-7.09 7.54-7.50 DMO method Dubé et al (1985) Schaphechinus mirabilis 6.8 7.34 Microfluorometry using pyranine Hamaguchi et al (1997) Hemicentrotus pulcherrimus 6.81 7.32…”

Section: Methodsmentioning

confidence: 99%

“…exchanger which contributes to the regulation of pH i and Na ? content of the eggs independently of metabolic energy (Payan et al 1983;Girard et al 1982). Payan et al (1983) stated that the increased pH i at fertilization is maintained by an Na ?…”

Section: Oa Effects On Fertilization Successmentioning

confidence: 99%

CO2-induced fertilization impairment in Strongylocentrotus droebachiensis collected in the Arctic

2014

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Fertilization depends on distribution and aggregation patterns of sea urchins which influence gamete contact time and may potentially enhance their vulnerability to ocean acidification. In this study, we conducted fertilization experiments to assess the effects of selected pH scenarios on fertilization success of Strongylocentrotus droebachiensis, from Spitsbergen, Arctic. Acidification was achieved by aerating seawater with different CO 2 partial pressures to represent preindustrial and present conditions (measured *180-425 latm) and future acidification scenarios (*550-800, *1,300, *2,000 latm). Fertilization success was defined as the proportion of successful/unsuccessful fertilizations per treatment; eggs were classified according to features of their fertilization envelope (FE), hyaline layer (HL) and achievement of cellular division. The diagnostic findings of specific pathological aberrations were described in detail. We additionally measured intracellular pH changes in unfertilized eggs exposed for 1 h to selected acidification treatments using BCECF/AM. We conclude that (a) acidified conditions increase the proportion of eggs that failed fertilization, (b) acidification may increase the risk of polyspermy due to failures in the FE formation supported by the occasional observation of multiple sperms in the perivitelline space and (c) irregular formation of the embryo may arise due to impaired formation of the HL. The decrease in fertilization success could be also related to the observed changes in intracellular pH at pCO 2 * 1,000 latm or higher.

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“…However the concentrations effective in sea urchin eggs are similar to those used to affect reconsituted channels preparations from muscle or brain (1,31). Furthermore, by experience we do know that drugs that affect specific ion movements in sea urchin eggs (ouabain, amiloride) have to be used at much higher concentrations than in mammalian cells (18,26,6).…”

Section: Ryanodine Affects Intracellular Calcium Sequestrationmentioning

confidence: 99%

Ryanodine Activates Sea Urchin Eggs

et al. 1992

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We have studied the effect on sea urchin eggs of ryanodine, a plant alkaloid that causes muscle contraction by opening calcium channels in the sarcoplasmic reticulum terminal cisternae. Ryanodine, although it is less effective that IP3, produces full or partial activation in 62% of injected sea urchin eggs. In addition ryanodine inhibits in a dose dependant manner 45Ca pumping in the isolated egg cortex or in eggs permeabilized with digitonin. Efflux experiments show that in fact ryanodine as IPS stimulates the release of calcium sequestered intracellularly. We further show that these effects of ryanodine are inhibited by Mg++, ruthenium red and heparin. Our results suggest that ryanodine-sensitive intracellular calcium channels exist in the sea urchin egg.

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Mechanisms regulating intracellular pH in sea urchin eggs

Cited by 66 publications

References 23 publications

Inactivation of MAPK in mature oocytes triggers progression into mitosis via a Ca2+-dependent pathway but without completion of S phase

Inactivation of MAPK in mature oocytes triggers progression into mitosis via a Ca2+-dependent pathway but without completion of S phase

CO2-induced fertilization impairment in Strongylocentrotus droebachiensis collected in the Arctic

Ryanodine Activates Sea Urchin Eggs

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