Possible role for Ca(2+) calmodulin-dependent protein kinase II as an effector of the fertilization Ca(2+) signal in mouse oocyte activation.
The present study shows that Ca(2+) calmodulin-dependent protein kinase II (CaM kinase II) is physiologically activated in fertilized mouse oocytes and is involved in the Ca(2+) response pathways that link the fertilization Ca(2+) signal to meiosis resumption and cortical granule (CG) exocytosis. After 10 min of insemination, CaM kinase II activity increased transiently, then peaked at 1 h and remained elevated 30 min later when most of the oocytes had completed the emission of the second polar body. In contrast, in ethanol-activated oocytes the early transient activation of CaM kinase II in response to a monotonic Ca(2+) rise was not followed by any subsequent increase. Inhibition of CaM kinase II by 20 micromol/l myristoylated-AIP (autocamtide-2-related inhibitory peptide) negatively affected MPF (maturing promoting factor) inactivation, cell cycle resumption and CG exocytosis in both fertilized and ethanol-activated oocytes. These results indicate that the activation of CaM kinase II in mouse oocytes is differently modulated by a monotonic or repetitive Ca(2+) rise and that it is essential for triggering regular oocyte activation.
Tatone
C
C
Centre for Assisted Reproduction and Department of Biomedical Sciences and Technologies, University of L'Aquila, Via Vetoio, Italy. ctatone@univaq.it
Delle Monache
S
S
Iorio
R
R
Caserta
D
D
Di Cola
M
M
Colonna
R
R
D000818:Animals; D002118:Calcium / Q000502:physiology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000187:drug effects / Q000502:physiology*; D005089:Exocytosis / Q000502:physiology; D005260:Female; D005306:Fertilization / Q000502:physiology*; D000090204:Mesothelin; D051379:Mice; D009865:Oocytes / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*
C000715528:Msln protein, mouse; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D000090204:Mesothelin; D002118:Calcium