The WD40 protein Morg1 facilitates Par6-aPKC binding to Crb3 for apical identity in epithelial cells

Junya Hayase, Sachiko Kamakura, Yuko Iwakiri, Yoshihiro Yamaguchi, Tomoko Izaki, Takashi Ito, Hideki Sumimoto

Research output: Contribution to journalArticlepeer-review

26 Citations (Scopus)


Formation of apico-basal polarity in epithelial cells is crucial for both morphogenesis (e.g., cyst formation) and function (e.g., tight junction development). Atypical protein kinase C (aPKC), complexed with Par6, is considered to translocate to the apical membrane and function in epithelial cell polarization. However, the mechanism for translocation of the Par6-aPKC complex has remained largely unknown. Here, we show that the WD40 protein Morg1 (mitogen-activated protein kinase organizer 1) directly binds to Par6 and thus facilitates apical targeting of Par6-aPKC in Madin-Darby canine kidney epithelial cells. Morg1 also interacts with the apical transmembrane protein Crumbs3 to promote Par6- aPKC binding to Crumbs3, which is reinforced with the apically localized small GTPase Cdc42. Depletion of Morg1 disrupted both tight junction development in monolayer culture and cyst formation in three-dimensional culture; apico-basal polarity was notably restored by forced targeting of aPKC to the apical surface. Thus, Par6-aPKC recruitment to the premature apical membrane appears to be required for definition of apical identity of epithelial cells.

Original languageEnglish
Pages (from-to)635-650
Number of pages16
JournalJournal of Cell Biology
Issue number5
Publication statusPublished - Mar 2013
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Cell Biology


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