Microtubule plus-end and minus-end capture at adherens junctions is involved in the assembly of apico-basal arrays in polarised epithelial cells

Cell Motil Cytoskeleton. 2009 Oct;66(10):893-908. doi: 10.1002/cm.20393.

Abstract

Apico-basal polarisation of epithelial cells involves a dramatic reorganisation of the microtubule cytoskeleton. The classic radial array of microtubules focused on a centrally located centrosome typical of many animal cells is lost or greatly reduced and a non-centrosomal apico-basal array develops. The molecules and mechanisms responsible for the assembly and positioning of these non-centrosomal microtubules have not been fully elucidated. Using a Nocodazole induced regrowth assay in invitro culture (MDCK) and in situ epithelial (cochlear Kolliker's) cell models we establish that the apico-basal array originates from the centrosome and that the non-centrosomal microtubule minus-end anchoring sites do not contribute significantly to their nucleation. Confocal and electron microscopy revealed that an extended radial array assembles with microtubule plus-ends targeting cadheren sites at adherens junctions and EB1 and CLIP-170 co-localising with beta-catenin and dynein clusters at the junction sites. The extended radial array is likely to be a vital intermediate step in the assembly process with cortical anchored dynein providing the mechanical force required for microtubule release, translocation and capture. Ultrastructural analyses of the apico-basal arrays in fully polarised MDCK and Kolliker's cells revealed microtubule minus-end association with the most apical adherens junction (Zonula adherens). We propose that a release and capture model involving both microtubule plus- and minus-end capture at adherens junctions is responsible for the generation of non-centrosomal apico-basal arrays in most centrosome containing polarised epithelial cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adherens Junctions / metabolism*
  • Animals
  • Cadherins / metabolism
  • Cells, Cultured
  • Centrosome / metabolism
  • Centrosome / ultrastructure
  • Dogs
  • Dyneins / metabolism
  • Epithelial Cells / metabolism
  • Microtubules / drug effects
  • Microtubules / physiology*
  • Microtubules / ultrastructure
  • Nocodazole / pharmacology
  • Tubulin Modulators / metabolism

Substances

  • Cadherins
  • Tubulin Modulators
  • Dyneins
  • Nocodazole