The Drosophila PAR-1 spacer domain is required for lateral membrane association and for polarization of follicular epithelial cells

Curr Biol. 2005 Feb 8;15(3):255-61. doi: 10.1016/j.cub.2005.01.033.


The Ser/Thr kinases of the PAR-1/MARK/Kin1 family are conserved regulators of polarity in epithelial and non-epithelial cells . Drosophila PAR-1 localizes laterally in the follicular epithelium of the ovary , where it has been shown to function at two distinct levels: It stabilizes the cytoskeleton and it regulates apical-basal polarity by directly inhibiting lateral assembly of the apical aPKC/Bazooka/PAR-6 complex . However, it has been unclear how lateral localization of Drosophila PAR-1 is achieved and whether this localization contributes to epithelial polarity in vivo. Here we show that, through its spacer domain, Drosophila PAR-1 accumulates on the lateral plasma membrane (PM) in cells of the follicular epithelium (FE). Rescue experiments indicate that in FE cells PAR-1 kinase activity is essential for all the described functions of PAR-1. In contrast, the spacer domain of PAR-1 is required for apical-basal polarity and growth control but is dispensable for microtubule (MT) stabilization. Our data indicate that the spacer domain of PAR-1 is required for lateral PM localization of PAR-1 kinase and for development of a polarized FE.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • Cell Membrane / metabolism
  • Cell Polarity / genetics*
  • Cells, Cultured
  • DNA Primers
  • Drosophila Proteins / genetics*
  • Drosophila Proteins / metabolism
  • Drosophila melanogaster / genetics*
  • Epithelium / metabolism
  • Epithelium / ultrastructure
  • Female
  • Fluorescent Antibody Technique
  • Glycogen Synthase Kinase 3
  • Green Fluorescent Proteins
  • Microscopy, Electron, Transmission
  • Molecular Sequence Data
  • Ovarian Follicle / metabolism*
  • Protein Kinases / genetics*
  • Protein Kinases / metabolism
  • Protein Structure, Tertiary
  • Protein-Serine-Threonine Kinases / metabolism
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Transgenes / genetics


  • DNA Primers
  • Drosophila Proteins
  • Green Fluorescent Proteins
  • Protein Kinases
  • Protein-Serine-Threonine Kinases
  • Glycogen Synthase Kinase 3
  • Par-1 protein, Drosophila