Protein kinase C, a pivotal regulator of hamster egg activation, functions after elevation of intracellular free calcium

Developmental Biology
G I GallicanoD G Capco

Abstract

We investigated the signal transduction pathways that mediate activation of Syrian hamster eggs. Under conditions in which the concentration of intracellular free calcium ([Ca2+]i) is clamped low, activation of protein kinase C (PKC) can induce second polar body formation, reformation of the nuclear envelope, and decondensation of chromatin, as well as golgi reformation. However, calcium is necessary for normal transition from meiotic metaphase II to anaphase II. Conversely, under conditions in which the level of PKC activity is clamped low, induction of a rise in [Ca2+]i, using the calcium ionophore A23187, does not induce egg activation. These results strongly suggest that PKC acts after the calcium signal as a proximal inducer of egg activation. This suggestion is supported by the kinetics of egg activation; PKC stimulators activate the eggs at a significantly enhanced rate (P < 0.01) compared with activation by calcium ionophore. We show here that PKC stimulators induce emission of the second polar body, but that subsequently, with longer culture, the emitted polar body is absorbed. Our results suggest that the rise in [Ca2+]i serves two functions, to activate PKC and to induce the transition from metaphase II to anaphase I...Continue Reading

Citations

Apr 1, 1997·Molecular Reproduction and Development·G I GallicanoD G Capco
Sep 18, 1997·Molecular Reproduction and Development·R ColonnaL Di Francesco
Oct 15, 1998·Molecular Reproduction and Development·T RazR Shalgi
Sep 2, 1999·Molecular Reproduction and Development·C M Pauken, D G Capco
Dec 4, 2001·Journal of Reproductive Immunology·Efrat EliyahuRuth Shalgi
May 4, 2002·Molecular and Cellular Endocrinology·Anat Talmor-CohenRuth Shalgi
Oct 14, 2008·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·Osamu Morita, Madhusudan G Soni
May 27, 2008·Food and Chemical Toxicology : an International Journal Published for the British Industrial Biological Research Association·Osamu MoritaMark D Nemec
May 9, 2012·Journal of Cellular Physiology·Jose Raul Gonzalez-GarciaKarl Swann
Dec 14, 2004·Biochimica Et Biophysica Acta·Guillaume Halet
Sep 10, 2004·Developmental Biology·D Page BaluchDavid G Capco
Jun 25, 2002·Biology of Reproduction·Efrat Eliyahu, Ruth Shalgi
Sep 7, 2004·Molecular Reproduction and Development·Dazhi YangWilliam R Eckberg
Jan 1, 1997·BioEssays : News and Reviews in Molecular, Cellular and Developmental Biology·G I GallicanoD G Capco
Jan 22, 2020·Journal of Cellular Physiology·Weber Beringui FeitosaMayra Elena Ortiz D'Avila Assumpção
Jul 14, 2009·Brain Research·Sudarshana PurkayasthaProbal Banerjee

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