title: A novel function for the PAR complex in subcellular morphogenesis of tracheal terminal cells in Drosophila melanogaster.
abstract: The processes that generate cellular morphology are not well understood. To investigate this problem, we use Drosophila melanogaster tracheal terminal cells, which undergo two distinct morphogenetic processes: subcellular branching morphogenesis and subcellular apical lumen formation. Here we show these processes are regulated by components of the PAR-polarity complex. This complex, composed of the proteins Par-6, Bazooka (Par-3), aPKC, and Cdc42, is best known for roles in asymmetric cell division and apical/basal polarity. We find Par-6, Bazooka, and aPKC, as well as known interactions between them, are required for subcellular branch initiation, but not for branch outgrowth. By analysis of single and double mutants, and isolation of two novel alleles of Par-6, one of which specifically truncates the Par-6 PDZ domain, we conclude that dynamic interactions between apical PAR-complex members control the branching pattern of terminal cells. These data suggest that canonical apical PAR-complex activity is required for subcellular branching morphogenesis. In addition, we find the PAR proteins are downstream of the FGF pathway that controls terminal cell branching. In contrast, we find that while Par-6 and aPKC are both required for subcellular lumen formation, neither Bazooka nor a direct interaction between Par-6 and aPKC is needed for this process. Thus a novel, noncanonical role for the polarity proteins Par-6 and aPKC is used in formation of this subcellular apical compartment. Our results demonstrate that proteins from the PAR complex can be deployed independently within a single cell to control two different morphogenetic processes.
authors.affiliation: Department of Human Genetics, University of Utah, Salt Lake City, Utah 84112, USA.
authors.forename: Tiffani A
authors.initials: TA
authors.lastname: Jones
authors.forename: Mark M
authors.initials: MM
authors.lastname: Metzstein
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology* / Q000196:embryology / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D042541:Intracellular Space / Q000378:metabolism; D009024:Morphogenesis; D054731:PDZ Domains; D011493:Protein Kinase C / Q000378:metabolism*; D021381:Protein Transport; D015398:Signal Transduction; D014132:Trachea / Q000166:cytology
chemical_list: D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; C400774:baz protein, Drosophila; D005346:Fibroblast Growth Factors; C115015:PKC-3 protein; C532584:Par-6 protein, Drosophila; D011493:Protein Kinase C