Microtubules provide directional information for core PCP function.
Bottom Line: Consistent with previous results, we find that the Ft/Ds/Fj-module has an effect on a MT-cytoskeleton.We show Ft/Ds/Fj-dependent initial polarization of the apical MT-cytoskeleton prior to global alignment of the core-module, reveal that the anchoring of apical non-centrosomal MTs at apical junctions is polarized, observe that directional trafficking of vesicles containing Dsh depends on Ft, and demonstrate the feasibility of this model by mathematical simulation.Together, these results support the hypothesis that Ft/Ds/Fj provides a signal to orient core PCP function via MT polarization.
Affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, United States email@example.com.Show MeSH
Related in: MedlinePlus
Mentions: It has been suggested that PCP defects in ds and ft mutants may be due to activation of the Hippo tumor suppressor pathway, which is also controlled by Ft/Ds/Fj, because ft mutant larval wing discs with rescued Hippo signaling show only weak PCP defects limited to the most proximal part of the wing despite the clonal PCP phenotypes observed in pupal and adult wings (Brittle et al., 2012). To better assess whether the Ft/Ds/Fj pathway modulates the MT cytoskeleton independent of Hippo signaling, and to do so across the expanse of the wing, we analyzed ft mutant flies rescued with FtΔECDΔN-1, a truncated form of Ft lacking a PCP signaling domain (Matakatsu and Blair, 2012). These flies are deficient for PCP signaling, but competent for Hippo pathway regulation. They showed PCP defects in the proximal-central part of the adult wing, displaying swirling patterns reminiscent of those in ft clones (Ma et al., 2003) (Figure 3A; Matakatsu and Blair, 2012). At 24 hAPF, MTs in the proximal and central part of the wing, where hair polarity is often disturbed, were randomized (Figure 3A,A′, Figure 3—figure supplement 5A,A′). In contrast, the peripheral and distal regions of these wings had more coherent hair polarity, with hairs pointing more toward the wing margin than in wildtype wings (Figure 3A), mirroring the orientation of core PCP protein domains (Figure 3—figure supplement 5A,A″). In these peripheral regions, MTs were ordered and oriented with the hairs and core PCP domains (Figure 3A″). Flies in which the Ds and Fj gradients were removed showed an essentially identical phenotype (ds38kfjN7/dsUA071fjd1; UAS-Ds/TubP-Gal4;Figure 3—figure supplement 5B–B″). Finally, MT orientation was randomized in ft or ds clones in the same proximal part of the wing where it is disturbed in ft mutant wings rescued for Hippo signaling (Figure 3—figure supplement 5C; see also [Ma et al., 2008]). These data show that in the central part of pupal wings, MT orientation, core PCP protein polarity and adult polarity are strongly dependent on PCP signaling through Ft (Figure 3—figure supplements 5 and 6). They also suggest the existence of an additional signal, perhaps from the wing margin, that can orient MTs in the periphery of the wing.10.7554/eLife.02893.009Figure 3.MTs are misaligned in ft and ds mutant wing.
Affiliation: Department of Pathology, Stanford University School of Medicine, Stanford, United States firstname.lastname@example.org.