The Xenopus IP3 receptor: Structure, function, and localization in oocytes and eggs

Shoen Kume, Akira Muto, Jun Aruga, Toshiyuki Nakagawa, Takayuki Michikawa, Teiichi Furuichi, Shinji Nakade, Hideyuki Okano, Katsuhiko Mikoshiba

Research output: Contribution to journalArticlepeer-review

215 Citations (Scopus)


To study the role of the IP3 receptor (IP3R) upon egg activation, cDNA clones encoding IP3R expressed in the Xenopus oocytes were isolated. By analyses of the primary structure and functional expression of the cDNA, Xenopus IP3R (XIP3R) was shown to have an IP3-binding domain and a putative Ca2+ channel region. Immunocytochemical studies revealed polarized distribution of XIP3R in the cytoplasm of the animal hemisphere in a well-organized endoplasmic reticulum-like structure and intensive localization in the perinuclear region of stage VI immature oocytes. In ovulated unfertilized eggs, XIP3R was densely enriched in the cortical region of both hemispheres in addition to its polarized localization. After fertilization, XIP3R showed a drastic change in its distribution in the cortical region. These results imply the predominant role of the XIP3R in both the formation and propagation of Ca2+ waves at fertilization.

Original languageEnglish
Pages (from-to)555-570
Number of pages16
Issue number3
Publication statusPublished - 1993 May 7
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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