title: Tissue-specific function of Patj in regulating the Crumbs complex and epithelial polarity.
abstract: Patj is described as a core component of the Crumbs complex. Along with the other components, Crumbs and Stardust, Patj has been proposed as essential for epithelial polarity. However, no proper in vivo genetic analysis of Patj function has been performed in any organism. We have generated the first null mutants for Drosophila Patj. These mutants are lethal. However, Patj is not required in all epithelia where the Crumbs complex is essential. Patj is dispensable for ectoderm polarity and embryonic development, whereas more severe defects are observed in the adult follicular epithelium, including mislocalisation of the Crumbs complex from the apical domain, as well as morphogenetic defects. These defects are similar to those observed with crumbs and stardust mutants, although weaker and less frequent. Also, gain-of-function of Crumbs and Patj mutation genetically suppress each other in follicular cells. We also show that the first PDZ domain of Patj associated with the Stardust-binding domain are sufficient to fully rescue both Drosophila viability and Crumbs localisation. We propose that the only crucial function of Patj hinges on the ability of its first two domains to positively regulate the Crumbs complex, defining a new developmental level of regulation of its dynamics.
authors.affiliation: GReD Laboratory, Faculté de Médecine, UMR CNRS 6293, Clermont Université, INSERM U1103, place Henri-Dunant, 63000 Clermont-Ferrand, France.
authors.forename: Clothilde
authors.initials: C
authors.lastname: Pénalva
authors.forename: Vincent
authors.initials: V
authors.lastname: Mirouse
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D016764:Cell Polarity / Q000235:genetics*; D004330:Drosophila / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D004625:Embryo, Nonmammalian; D004843:Epistasis, Genetic / Q000235:genetics / Q000502:physiology; D004848:Epithelium / Q000196:embryology* / Q000378:metabolism; D005136:Eye Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D051528:Guanylate Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism* / Q000502:physiology*; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D046912:Multiprotein Complexes / Q000235:genetics / Q000378:metabolism; D009928:Organ Specificity / Q000235:genetics; D054730:Protein Interaction Domains and Motifs / Q000235:genetics / Q000502:physiology; D055503:Protein Multimerization / Q000235:genetics
chemical_list: D029721:Drosophila Proteins; D005136:Eye Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D046912:Multiprotein Complexes; C501446:PATJ protein, Drosophila; C064360:crb protein, Drosophila; D051528:Guanylate Kinases; C444479:sdt protein, Drosophila