Figure 8.

Inhibition of aPKCζ impairs the regulated formation of a solitary lumen at the two-cell stage. GFP-Crb3a–expressing MDCKII cells were embedded in Geltrex as described. In some specimens, myristoylated aPKCζ pseudosubstrate (Calbiochem) was added to the liquid medium as indicated. Cells were fixed 24 h after embedding and stained with the indicated antibodies. (A, collapsed Z-stacks) In untreated cells, the majority of two-cell stages showed regular lumen formation, (subpanel a), whereas inhibitor-treated cells either showed ectopic localization of apical or tight junction components (subpanel c arrowhead) or occasionally had more than one lumen (subpanel b, arrows). (B) Quantification of two-cell stages with impaired lumen formation (ectopic localization of apical or tight junction components or multiple lumina) in aPKCζ pseudosubstrate–treated cells versus untreated cells.