Translator Disclaimer
1 July 2002 Activation of Protein Kinase C Induces Mitogen-Activated Protein Kinase Dephosphorylation and Pronucleus Formation in Rat Oocytes
Author Affiliations +
Abstract

Mammalian oocytes are arrested at metaphase of the second meiotic division (MII) before fertilization. When oocytes are stimulated by spermatozoa, they exit MII stage and complete meiosis. It has been suggested that an immediate increase in intracellular free calcium concentration and inactivation of maturation promoting factor (MPF) are required for oocyte activation. However, the underlying mechanism is still unclear. In the present study, we investigated the role of protein kinase C (PKC) and mitogen-activated protein (MAP) kinase, and their interplay in rat oocyte activation. We found that MAP kinase became dephosphorylated in correlation with pronucleus formation after fertilization. Protein kinase C activators, phorbol 12-myriatate 13-acetate (PMA) and 1,2-dioctanoyl-rac-glycerol (diC8), triggered dephosphorylation of MAP kinase and pronucleus formation in a dose-dependent and time-dependent manner. Dephosphorylation of MAP kinase was also correlated with pronucleus formation when oocytes were treated with PKC activators. Effects of PKC activators were abolished by the PKC inhibitors, calphostin C and staurosporine, as well as a protein phosphatase blocker, okadaic acid (OA). These results suggest that PKC activation may cause rat oocyte pronucleus formation via MAP kinase dephosphorylation, which is probably mediated by OA-sensitive protein phosphatases. We also provide evidence supporting the involvement of such a process in fertilization.

Qing Lu, Gary D. Smith, Da-Yuan Chen, Zhi-Ming Han, and Qing-Yuan Sun "Activation of Protein Kinase C Induces Mitogen-Activated Protein Kinase Dephosphorylation and Pronucleus Formation in Rat Oocytes," Biology of Reproduction 67(1), 64-69, (1 July 2002). https://doi.org/10.1095/biolreprod67.1.64
Received: 3 July 2001; Accepted: 1 January 2002; Published: 1 July 2002
JOURNAL ARTICLE
6 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top