title: The Drosophila MAST kinase Drop out is required to initiate membrane compartmentalisation during cellularisation and regulates dynein-based transport.
abstract: Cellularisation of the Drosophila syncytial blastoderm embryo into the polarised blastoderm epithelium provides an excellent model with which to determine how cortical plasma membrane asymmetry is generated during development. Many components of the molecular machinery driving cellularisation have been identified, but cell signalling events acting at the onset of membrane asymmetry are poorly understood. Here we show that mutations in drop out (dop) disturb the segregation of membrane cortical compartments and the clustering of E-cadherin into basal adherens junctions in early cellularisation. dop is required for normal furrow formation and controls the tight localisation of furrow canal proteins and the formation of F-actin foci at the incipient furrows. We show that dop encodes the single Drosophila homologue of microtubule-associated Ser/Thr (MAST) kinases. dop interacts genetically with components of the dynein/dynactin complex and promotes dynein-dependent transport in the embryo. Loss of dop function reduces phosphorylation of Dynein intermediate chain, suggesting that dop is involved in regulating cytoplasmic dynein activity through direct or indirect mechanisms. These data suggest that Dop impinges upon the initiation of furrow formation through developmental regulation of cytoplasmic dynein.
authors.affiliation: Division of Cell and Developmental Biology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Hain
authors.forename: Alistair
authors.initials: A
authors.lastname: Langlands
authors.forename: Hannah C
authors.initials: HC
authors.lastname: Sonnenberg
authors.forename: Charlotte
authors.initials: C
authors.lastname: Bailey
authors.forename: Simon L
authors.initials: SL
authors.lastname: Bullock
authors.forename: H-Arno J
authors.initials: HA
authors.lastname: Müller
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D030801:Animals, Genetically Modified; D002451:Cell Compartmentation / Q000235:genetics*; D002462:Cell Membrane / Q000502:physiology*; D016764:Cell Polarity / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000201:enzymology / Q000235:genetics; D004398:Dyneins / Q000378:metabolism*; D004625:Embryo, Nonmammalian; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000502:physiology*; D009024:Morphogenesis / Q000235:genetics; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology*; D021381:Protein Transport / Q000235:genetics; D017385:Sequence Homology
chemical_list: D000199:Actins; D029721:Drosophila Proteins; D008869:Microtubule-Associated Proteins; C000589222:Dop protein, Drosophila; D017346:Protein Serine-Threonine Kinases; D004398:Dyneins
keywords: Cell polarity; Drosophila; Dynein; Microtubules; Protein kinase