title: Ninein is released from the centrosome and moves bi-directionally along microtubules.
abstract: Cell-to-cell contact and polarisation of epithelial cells involve a major reorganisation of the microtubules and centrosomal components. The radial microtubule organisation is lost and an apico-basal array develops that is no longer anchored at the centrosome. This involves not only the relocation of microtubules but also of centrosomal anchoring proteins to apical non-centrosomal sites. The relocation of microtubule minus-end-anchoring proteins such as ninein to the apical sites is likely to be essential for the assembly and stabilisation of the apico-basal arrays in polarised epithelial cells. In this study, we establish that ninein is highly dynamic and that, in epithelial cells, it is present not only at the centrosome but also in the cytoplasm as distinct speckles. Live-cell imaging reveals that GFP-ninein speckles are released from the centrosome and move in a microtubule-dependent manner within the cytoplasm and thus establishes that epithelial cells possess the mechanical means for relocation of ninein to non-centrosomal anchoring sites. We also provide evidence for the deployment of ninein speckles to apical anchoring sites during epithelial differentiation in both an in situ tissue and an in vitro culture system. In addition, the findings suggest that the non-centrosomal microtubule anchoring sites associate with adherens junctions in polarised epithelial cells.
authors: School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
authors: David K
authors: DK
authors: Moss
authors: Gemma
authors: G
authors: Bellett
authors: Jane M
authors: JM
authors: Carter
authors: Mirjana
authors: M
authors: Liovic
authors: Jennifer
authors: J
authors: Keynton
authors: Alan R
authors: AR
authors: Prescott
authors: E Birgitte
authors: EB
authors: Lane
authors: Mette M
authors: MM
authors: Mogensen
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism; D002454:Cell Differentiation / Q000502:physiology; D002460:Cell Line; D018385:Centrosome / Q000378:metabolism*; D003593:Cytoplasm / Q000378:metabolism; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D007758:Ear, Inner / Q000033:anatomy & histology / Q000254:growth & development; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D038362:Glycogen Synthase Kinase 3 / Q000037:antagonists & inhibitors; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D051379:Mice; D008870:Microtubules / Q000378:metabolism*; D015739:Nocodazole / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D053778:Thiazolidines / Q000378:metabolism; D050257:Tubulin Modulators / Q000378:metabolism
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D003598:Cytoskeletal Proteins; C512806:NIN protein, human; D009687:Nuclear Proteins; D011993:Recombinant Fusion Proteins; D053778:Thiazolidines; D050257:Tubulin Modulators; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; C037068:latrunculin B; D015739:Nocodazole