Establishment of cell polarity by afadin during the formation of embryoid bodies

Authors

  • Hitomi Komura,

    1. Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita, Osaka 565-0871, Japan
    Search for more papers by this author
  • Hisakazu Ogita,

    1. Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita, Osaka 565-0871, Japan
    Search for more papers by this author
  • Wataru Ikeda,

    1. Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita, Osaka 565-0871, Japan
    Search for more papers by this author
  • Akira Mizoguchi,

    1. Department of Neural Regeneration and Cell Communication, Mie University Graduate School of Medicine, Tsu, Mie 514-8507, Japan
    Search for more papers by this author
  • Jun Miyoshi,

    1. Department of Molecular Biology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka 537-8511, Japan
    Search for more papers by this author
  • Yoshimi Takai

    Corresponding author
    1. Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita, Osaka 565-0871, Japan
    2. Division of Molecular and Cellular Biology, Department of Biochemistry and Molecular Biology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0017, Japan
    Search for more papers by this author

  • Communicated by: Eisuke Nishida

Correspondence: E-mail: ytakai@med.kobe.u.ac.jp

Abstract

Afadin directly links nectin, an immunoglobulin-like cell–cell adhesion molecule, to actin filaments (F-actin) at adherens junctions (AJs). The nectin–afadin complex is important for the formation of not only AJs but also tight junctions (TJs) in epithelial cells. Studies using afadin-knockout mice have revealed that afadin is indispensable for embryonic development by organizing the formation of cell–cell junctions. However, the molecular mechanism of cell–cell junction disorganization during embryonic development in afadin-knockout mice is poorly understood. To address this, we took advantage of embryoid bodies (EBs) as a model system. The formation of cell–cell junctions including AJs and TJs was impaired in afadin-null EBs. The proper accumulation of the Par complex and the activation of Cdc42 and atypical PKC (aPKC), which are crucial for the formation of cell polarity, were also inhibited by knockout of afadin. In addition, the disruption of afadin caused the abnormal deposition of laminin and the dislocalization of its receptors integrin α6 and integrin β1. These results indicate that afadin organizes the formation of cell–cell junctions by regulating cell polarization in early embryonic development.

Ancillary