title: Interaction of Par-6 and Crumbs complexes is essential for photoreceptor morphogenesis in Drosophila.
abstract: Apicobasal cell polarity is crucial for morphogenesis of photoreceptor rhabdomeres and adherens junctions (AJs) in the Drosophila eye. Crumbs (Crb) is specifically localized to the apical membrane of photoreceptors, providing a positional cue for the organization of rhabdomeres and AJs. We show that the Crb complex consisting of Crb, Stardust (Sdt) and Discs-lost (Dlt) colocalizes with another protein complex containing Par-6 and atypical protein kinase C (aPKC) in the rhabdomere stalk of photoreceptors. Loss of each component of the Crb complex causes age-dependent mislocalization of Par-6 complex proteins, and ectopic expression of Crb intracellular domain is sufficient to recruit the Par-6 complex. We also show that the absence of Par-6 complex proteins results in severe mislocalization and loss of Crb complex. We further demonstrate that Dlt directly binds to Par-6, providing a molecular basis for the mutual dependence of the two complexes. These results suggest that the interaction of Crb and Par-6 complexes is required for the organization and maintenance of apical membranes and AJs of photoreceptors.
authors.affiliation: Department of Molecular and Cellular Biology, Baylor College of Medicine, TX 77030, USA.
authors.forename: Sang-Chul
authors.initials: SC
authors.lastname: Nam
authors.forename: Kwang-Wook
authors.initials: KW
authors.lastname: Choi
mesh_terms: D022005:Adherens Junctions / Q000378:metabolism; D000818:Animals; D016764:Cell Polarity; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D051528:Guanylate Kinases; D006801:Humans; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism; D009024:Morphogenesis; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics / Q000378:metabolism; D017956:Photoreceptor Cells, Invertebrate / Q000166:cytology / Q000254:growth & development / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D011506:Proteins; D011993:Recombinant Fusion Proteins; C064360:crb protein, Drosophila; C118488:dlt protein, Drosophila; C115015:PKC-3 protein; D011493:Protein Kinase C; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases; C444479:sdt protein, Drosophila