Interaction of Par-6 and Crumbs complexes is essential for photoreceptor morphogenesis in Drosophila.
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.
Nam
Sang-Chul
SC
Department of Molecular and Cellular Biology, Baylor College of Medicine, TX 77030, USA.
Choi
Kwang-Wook
KW
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
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