title: Microtubule-induced Pins/Galphai cortical polarity in Drosophila neuroblasts.
abstract: Cortical polarity regulates cell division, migration, and differentiation. Microtubules induce cortical polarity in yeast, but few examples are known in metazoans. We show that astral microtubules, kinesin Khc-73, and Discs large (Dlg) induce cortical polarization of Pins/Galphai in Drosophila neuroblasts; this cortical domain is functional for generating spindle asymmetry, daughter-cell-size asymmetry, and distinct sibling fates. Khc-73 localizes to astral microtubule plus ends, and Dlg/Khc-73 and Dlg/Pins coimmunoprecipitate, suggesting that microtubules induce Pins/Galphai cortical polarity through Dlg/Khc-73 interactions. The microtubule/Khc-73/Dlg pathway acts in parallel to the well-characterized Inscuteable/Par pathway, but each provides unique spatial and temporal information: The Inscuteable/Par pathway initiates at prophase to coordinate neuroblast cortical polarity with CNS tissue polarity, whereas the microtubule/Khc-73/Dlg pathway functions at metaphase to coordinate neuroblast cortical polarity with the mitotic spindle axis. These results identify a role for microtubules in polarizing the neuroblast cortex, a fundamental step for generating cell diversity through asymmetric cell division.
authors.affiliation: Institutes of Neuroscience and Molecular Biology, Howard Hughes Medical Institute, University of Oregon, Eugene, Oregon 97403, USA.
authors.forename: Sarah E
authors.initials: SE
authors.lastname: Siegrist
authors.forename: Chris Q
authors.initials: CQ
authors.lastname: Doe
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D018797:Cell Cycle Proteins; D016764:Cell Polarity / Q000502:physiology*; D002478:Cells, Cultured; D004330:Drosophila; D029721:Drosophila Proteins / Q000378:metabolism* / Q000502:physiology; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000378:metabolism*; D016547:Kinesins / Q000502:physiology; D008677:Metaphase; D008870:Microtubules / Q000502:physiology*; D008954:Models, Biological; D009419:Nerve Tissue Proteins / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D008941:Spindle Apparatus / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000502:physiology
chemical_list: D018797:Cell Cycle Proteins; D029721:Drosophila Proteins; D020730:Guanine Nucleotide Dissociation Inhibitors; C104644:Khc-73 protein, Drosophila; D009419:Nerve Tissue Proteins; C405164:Pins protein, Drosophila; D025521:Tumor Suppressor Proteins; C070350:dlg1 protein, Drosophila; D016547:Kinesins; D019206:GTP-Binding Protein alpha Subunits, Gi-Go