Centrosome migration and apical membrane formation during epithelial polarization in MDCK cysts

Epithelial cell polarization is essential for their proper function. Key aspects involve the transportation and accumulation of polarity molecules to create the apical membrane (AM), or cell-to-cell junctions, and the centrosome's positioning at the AM site. However, the interplay among polarity molecules, AM formation, and centrosome positioning is not fully understood.

When cultured in Matrigel, a single epithelial cell often displays de novo polarization alongside cytokinesis. Upon mitotic exit, centrosomes migrate towards the future AM site, prompting questions about their contribution to polarization. In this study, researchers altered centrosomes and polarity regulators in Matrigel-cultured cells and manipulated polarization direction using suspension culture to investigate the relationships among polarization features.

Interestingly, centrosomal microtubules might not be essential for centrosome positioning or AM formation; however, their absence decreases the efficiency of AM formation. The polarity regulator Par3, rather than AM component trafficking, plays a significant role in centrosome positioning. In suspension culture, centrosomes migrate in the opposite direction to AM formation.

Overall, these findings elucidate the hierarchical relationships among multiple polarization features and reveal that centrosome-driven polarity is not universal in epithelial cells, shedding new light on the mechanisms behind epithelial polarization.