CaMKII can participate in but is not sufficient for the establishment of the membrane block to polyspermy in mouse eggs

Allison J. Gardner, Jason G. Knott, Keith T. Jones, Janice Perry Evans

Research output: Contribution to journalArticlepeer-review

Abstract

Fertilization triggers initiation of development and establishment of blocks on the egg coat and plasma membrane to prevent fertilization by multiple sperm (polyspermy). The mechanism(s) by which mammalian eggs establish the membrane block to polyspermy is largely unknown. Ca2+/calmodulin- dependent protein kinase II (CaMKII) appears to be the key regulator of several egg activation events (completion of meiosis, progression to embryonic interphase, recruitment of maternal mRNAs). Since sperm-induced increases in cytosolic Ca2+ play a role in establishment of the membrane block to polyspermy in mouse eggs, we hypothesized that CaMKII was a Ca 2+-dependent effector leading to this change in egg membrane function. To test this hypothesis, we modulated CaMKII activity in two ways: activating eggs parthenogenetically by introducing constitutively active CaMKIIa (CA-CaMKII) into unfertilized eggs, and inhibiting endogenous CaMKII in fertilized eggs with myristoylated autocamtide 2-related inhibitory peptide (myrAIP). We find that eggs treated with myrAIP establish a less effective membrane block to polyspermy than do control eggs, but that CA-CaMKII is not sufficient for membrane block establishment, despite the fact that CA-CaMKII-activated eggs undergo other egg activation events. This suggests that: (I) CaMKII activity contributes to the membrane block, but this not faithfully mimicked by CA-CaMKII and furthermore, other pathways, in addition to those activated by Ca2+ and CaMKII, also participate in membrane block establishment; (2) CA-CaMKII has a range of effects as a parthenogenetic trigger of egg activation (high levels of cell cycle resumption, modest levels of cortical granule exocytosis, and no membrane block establishment).

Original languageEnglish (US)
Pages (from-to)275-280
Number of pages6
JournalJournal of Cellular Physiology
Volume212
Issue number2
DOIs
StatePublished - Aug 2007

ASJC Scopus subject areas

  • Clinical Biochemistry
  • Cell Biology
  • Physiology

Fingerprint

Dive into the research topics of 'CaMKII can participate in but is not sufficient for the establishment of the membrane block to polyspermy in mouse eggs'. Together they form a unique fingerprint.

Cite this