Upstream Hippo pathway components localize to border cell–border cell contacts inside migrating clusters. (A) Migrating cluster at stage 9 labeled for F-actin with phalloidin staining, which localizes to the outer rim of the cluster. (B) Migrating cluster at stage 9 stained for aPKC. (C) Migrating cluster at stage 9 stained for Kib. (D) Migrating cluster at stage 9 stained for Ex. (E) Migrating cluster at stage 9 stained for Mer. (F) Migrating cluster at stage 9 stained for V5-tagged Zyxin. (G) Migrating cluster at stage 9 stained for Crb. (H) Migrating cluster at stage 9 stained for myc-Wts. Note that Crb, aPKC, and upstream Hippo pathway components localize to membranes inside the cluster, whereas Wts is cytoplasmic. slbo-GAL4 was used to express UAS-Ex (D), UAS-Mer (E), UAS.Zyxin-V5 (F), or UAS.myc-Wts (H). (I) Schematic diagram of F-actin polarization in a migrating border cell cluster. (J) Schematic diagram of Hippo pathway components localizing to the sites of contact between border cells (i.e., inner membranes). The active, phosphorylated forms of Hpo and Wts are thought to be localized in a complex with upstream Hippo pathway components. Bars, 5 µm.