Downregulation of store-operated Ca2+ entry during mammalian meiosis is required for the egg-to-embryo transition

Bora Lee, Gianpiero Palermo, Khaled Machaca

Research output: Contribution to journalArticle

16 Citations (Scopus)


A specialized Ca2+ transient at fertilization represents the universal driver for the egg-to-embryo transition. Ca2+ signaling remodels during oocyte maturation to endow the egg with the capacity to produce the specialized Ca2+ transient at fertilization, which takes the form of a single (e.g. Xenopus) or multiple (e.g. mouse) Ca2+ spikes depending on the species. Store-operated Ca2+ entry (SOCE) is the predominant Ca2+ influx pathway in vertebrate oocytes, and in Xenopus SOCE completely inactivates during meiosis. Here, we show that SOCE is downregulated during mouse meiosis, but remains active in mature metaphase II eggs. SOCE inhibition is due to a decreased ability of the Ca2+ sensor STIM1 to translocate to the cortical endoplasmic reticulum domain and due to internalization of Orai1. Reversing SOCE downregulation by overexpression of STIM1 and Orai1 prolongs the Ca2+ oscillations at egg activation and disrupts the egg-to-embryo transition. Thus, SOCE downregulation during mammalian oocyte maturation is a crucial determinant of the fertilization-specific Ca2+ transient, egg activation and early embryonic development.

Original languageEnglish
Pages (from-to)1672-1681
Number of pages10
JournalJournal of Cell Science
Issue number7
Publication statusPublished - 1 Apr 2013



  • Calcium oscillations
  • Egg-to-embryo transition
  • Mouse
  • Oocyte maturation
  • Orai1
  • STIM1
  • Store-operated calcium entry

ASJC Scopus subject areas

  • Cell Biology

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