title: β-catenin is a molecular switch that regulates transition of cell-cell adhesion to fusion.
abstract: When a sperm and an oocyte unite upon fertilization, their cell membranes adhere and fuse, but little is known about the factors regulating sperm-oocyte adhesion. Here we explored the role of β-catenin in sperm-oocyte adhesion. Biochemical analysis revealed that E-cadherin and β-catenin formed a complex in oocytes and also in sperm. Sperm-oocyte adhesion was impaired when β-catenin-deficient oocytes were inseminated with sperm. Furthermore, expression of β-catenin decreased from the sperm head and the site of an oocyte to which a sperm adheres after completion of sperm-oocyte adhesion. UBE1-41, an inhibitor of ubiquitin-activating enzyme 1, inhibited the degradation of β-catenin, and reduced the fusing ability of wild-type (but not β-catenin-deficient) oocytes. These results indicate that β-catenin is not only involved in membrane adhesion, but also in the transition to membrane fusion upon fertilization.
authors.affiliation: Department of Reproductive Biology, National Center for Child Health and Development, 2-10-1 Okura, Setagaya, Tokyo 157-8535, Japan.
authors.forename: Youki
authors.initials: Y
authors.lastname: Takezawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Yoshida
authors.forename: Kenji
authors.initials: K
authors.lastname: Miyado
authors.forename: Masahiro
authors.initials: M
authors.lastname: Sato
authors.forename: Akihiro
authors.initials: A
authors.lastname: Nakamura
authors.forename: Natsuko
authors.initials: N
authors.lastname: Kawano
authors.forename: Keiichi
authors.initials: K
authors.lastname: Sakakibara
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kondo
authors.forename: Yuichirou
authors.initials: Y
authors.lastname: Harada
authors.forename: Naoko
authors.initials: N
authors.lastname: Ohnami
authors.forename: Seiya
authors.initials: S
authors.lastname: Kanai
authors.forename: Mami
authors.initials: M
authors.lastname: Miyado
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Saito
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Hidenori
authors.initials: H
authors.lastname: Akutsu
authors.forename: Akihiro
authors.initials: A
authors.lastname: Umezawa
mesh_terms: D000818:Animals; D001483:Base Sequence; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000502:physiology*; D002459:Cell Fusion; D017931:DNA Primers; D005260:Female; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D016133:Polymerase Chain Reaction; D013084:Sperm-Ovum Interactions; D051176:beta Catenin / Q000378:metabolism / Q000502:physiology*
chemical_list: D015820:Cadherins; D017931:DNA Primers; D051176:beta Catenin