DmPAR-6 directs epithelial polarity and asymmetric cell division of neuroblasts in Drosophila.
The Drosophila protein Bazooka is required for both apical-basal polarity in epithelial cells and directing asymmetric cell division in neuroblasts. Here we show that the PDZ-domain protein DmPAR-6 cooperates with Bazooka for both of these functions. DmPAR-6 colocalizes with Bazooka at the apical cell cortex of epithelial cells and neuroblasts, and binds to Bazooka in vitro. DmPAR-6 localization requires Bazooka, and mislocalization of Bazooka through overexpression redirects DmPAR-6 to ectopic sites of the cell cortex. In the absence of DmPAR-6, Bazooka fails to localize apically in neuroblasts and epithelial cells, and is distributed in the cytoplasm instead. Epithelial cells lose their apical-basal polarity in DmPAR-6 mutants, asymmetric cell divisions in neuroblasts are misorientated, and the proteins Numb and Miranda do not segregate correctly into the basal daughter cell. Bazooka and DmPAR-6 are Drosophila homologues of proteins that direct asymmetric cell division in early Caenorhabditis elegans embryos, and our results indicate that homologous protein machineries may direct this process in worms and flies.
Petronczki
M
M
Research Institute of Molecular Pathology, Dr Bohr Gasse 7, A-1030 Vienna, Austria.
Knoblich
J A
JA
D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019521:Body Patterning / Q000235:genetics; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics; D002455:Cell Division / Q000502:physiology*; D016764:Cell Polarity / Q000502:physiology*; D004330:Drosophila / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian / Q000196:embryology / Q000378:metabolism; D004848:Epithelium / Q000196:embryology* / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D007605:Juvenile Hormones / Q000378:metabolism; D009420:Nervous System / Q000196:embryology* / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism; D011506:Proteins / Q000235:genetics / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; D007605:Juvenile Hormones; C107613:Mira protein, Drosophila; D011506:Proteins; C400774:baz protein, Drosophila; C060606:numb protein, Drosophila; C512642:par-6 protein, C elegans