title: Apical-basal polarity in Drosophila neuroblasts is independent of vesicular trafficking.
abstract: The possession of apical-basal polarity is a common feature of epithelia and neural stem cells, so-called neuroblasts (NBs). In Drosophila, an evolutionarily conserved protein complex consisting of atypical protein kinase C and the scaffolding proteins Bazooka/PAR-3 and PAR-6 controls the polarity of both cell types. The components of this complex localize to the apical junctional region of epithelial cells and form an apical crescent in NBs. In epithelia, the PAR proteins interact with the cellular machinery for polarized exocytosis and endocytosis, both of which are essential for the establishment of plasma membrane polarity. In NBs, many cortical proteins show a strongly polarized subcellular localization, but there is little evidence for the existence of distinct apical and basolateral plasma membrane domains, raising the question of whether vesicular trafficking is required for polarization of NBs. We analyzed the polarity of NBs mutant for essential regulators of the main exocytic and endocytic pathways. Surprisingly, we found that none of these mutations affected NB polarity, demonstrating that NB cortical polarity is independent of plasma membrane polarity and that the PAR proteins function in a cell type-specific manner.
authors.affiliation: Stammzellbiologie, Abteilung Anatomie und Zellbiologie, Georg-August-Universität Göttingen, 37077 Göttingen, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Halbsgut
authors.forename: Karen
authors.initials: K
authors.lastname: Linnemannstöns
authors.forename: Laura Isabel
authors.initials: LI
authors.lastname: Zimmermann
authors.forename: Andreas
authors.initials: A
authors.lastname: Wodarz
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D016764:Cell Polarity; D004330:Drosophila / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029721:Drosophila Proteins / Q000378:metabolism; D034281:Dynamins / Q000378:metabolism; D004705:Endocytosis; D005089:Exocytosis; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D058953:Neural Stem Cells / Q000166:cytology* / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D021381:Protein Transport
chemical_list: D029721:Drosophila Proteins; D047908:Intracellular Signaling Peptides and Proteins; C400774:baz protein, Drosophila; C532584:Par-6 protein, Drosophila; D011493:Protein Kinase C; D034281:Dynamins