sn-1,2-diacylglycerol and choline increase after fertilization in Xenopus laevis.

Abstract

sn-1,2-Diacylglycerol (DAG) mass and translocation of protein kinase C a and ,B to a membrane fraction increased -7 min after insemination of Xenopus laevis eggs. The DAG mass increase of 48 pmol (from 62 to 110 pmol/cell) was greater than that for inositol 1,4,5-trisphosphate (1P3; an increase of -170 fmol or -280-fold smaller than the DAG increase), and DAG peaks -5 min after IP3. Choline mass (a measure of phosphatidylcholine-specific phospholipase D) also peaked before DAG and the choline increase (134 pmol/cell) was greater than that of DAG. There was no detectable change in phosphocholine mass (a measure of phosphatidylcholine-specific phospholipase C). During first cleavage, DAG decreased, PKC translocation was low, and choline increased and peaked (whereas published work shows an increase in IP3 mass). Artificial elevation of intracellular calcium ([Ca2+]

Membrane Depolarization Increases Membrane PtdIns(4,5)P2 Levels through Mechanisms Involving PKC βII and PI4 Kinase

“…Studies have revealed that PtdIns(4,5)P 2 itself binds to a polybasic region in the C2 domain of PKC (32,33). Studies have shown that eleven PKC isozymes are present in Xenopus oocytes (21,22). We detected PKC ␣, ␤I, ␤II, ␦, and ⑀ isozymes in this present study (Fig.…”

“…PKC ␤II May Be Involved in the Effects of Membrane Depolarization-Previous studies indicate that all 11 known mammalian isozymes of PKC are present in Xenopus oocytes (21,22). However, after trying antibodies from different sources, we were only able to detect the presence of the PKC ␣, ␤I, ␤II, ␦, and ⑀ isozymes.…”

Effects of protein kinase C on parthenogenetic activation of pig oocytes using calcium ionophore or nitric oxide-donor

“…Raz et al (1998) demonstrated the relocalization of cPKC isotypes PKC-α and -β during the activation of rat oocytes. The activation of isotypes PKC-α a -β was also reported to occur during the activation of Xenopus oocytes (Stith et al, 1997). In our experiments, however, the activation of oocytes was not blocked either by hispidin (inhibitor of PKC-β) or by Go6976 (inhibitor of PKC-α, -β I ).…”

Phospho-Signaling at Oocyte Maturation and Fertilization: Set Up for Embryogenesis and Beyond Part II. Kinase Regulators and Substrates

“…In support of this, choline, another product of PC hydrolysis by PLD, is also accumulating in a similar time course of fertilization. Whether DG is involved in the activation of egg PKC remains to be clarified (Stith et al 1997). Production of DG has also been examined in mouse eggs (Stith et al 1997;Yu et al 2008).…”

“…Whether DG is involved in the activation of egg PKC remains to be clarified (Stith et al 1997). Production of DG has also been examined in mouse eggs (Stith et al 1997;Yu et al 2008). In this species, sperm-derived PLC seems to be mainly responsible for DG production and subsequent PKC activation.…”