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

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 complexed with Par6, is considered to translocate to the apical membrane and function in epithelial cell polarization. However, the mechanism for translocation of the 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-aduanyu1531 in Madin-Darby canine kidney epithelial cells. Morg1 also interacts with the apical transmembrane protein Crumbs3 to promote Par6-aduanyu1531 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 to the apical surface. Thus, Par6-aduanyu1531 recruitment to the premature apical membrane appears to be required for definition of apical identity of epithelial cells.

KEYWORDS: {{ getKeywords(articleDetailText.words) }}