Figure 4.—

Armadillo, E-cadherin, and α-catenin protein levels are increased significantly in lgl mutants, suggesting that the loss of lgl stabilizes adherens junctions. (A) Western blot comparing Armadillo, E-cadherin, and α-catenin protein levels in wild-type vs. lgl (M/Z) mutants, with β-tubulin used as a loading control. (B) Overall model of polarity regulation by Zw3 where it regulated the protein levels of both Arm and aPKC. Zw3's effect on Lgl is most likely indirect through its regulation of aPKC, but there may be a direct effect as well. One known upstream component is Dsh, which has a direct effect on both Zw3 and Lgl, but what signals are upstream of both of these molecules remains to be discovered. (C) Schematic representation of the genetic results from single and double mutants in the apical–basal and AJ machinery translated into predicted cell biological effects.