PAR proteins and the establishment of cell polarity during C. elegans development

Bioessays. 2005 Feb;27(2):126-35. doi: 10.1002/bies.20175.


Cells become polarized to develop functional specializations and to distribute developmental determinants unequally during division. Studies that began in the nematode C. elegans have identified a group of largely conserved proteins, called PAR proteins, that play key roles in the polarization of many different cell types. During initial stages of cell polarization, certain PAR proteins become distributed asymmetrically along the cell cortex and subsequently direct the localization and/or activity of other proteins. Here I discuss recent findings on how PAR proteins become and remain asymmetric in three different contexts during C. elegans development: anterior-posterior polarization of the one-cell embryo, apicobasal polarization of non-epithelial early embryonic cells, and apicobasal polarization of epithelial cells. Although polarity within each of these cell types requires PAR proteins, the cues and regulators of PAR asymmetry can differ.

Publication types

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

MeSH terms

  • 14-3-3 Proteins / physiology*
  • Animals
  • Body Patterning
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / physiology*
  • Cell Lineage
  • Cell Nucleus / metabolism
  • Chromatin / metabolism
  • Cytoplasm / metabolism
  • Embryo, Nonmammalian
  • Gene Expression Regulation, Developmental*
  • Green Fluorescent Proteins / metabolism
  • Meiosis
  • Microscopy, Fluorescence
  • Mitosis
  • Models, Biological
  • Protein Kinase C / physiology
  • Protein-Serine-Threonine Kinases / physiology*
  • Proteins / physiology


  • 14-3-3 Proteins
  • Caenorhabditis elegans Proteins
  • Chromatin
  • Proteins
  • par-2 protein, C elegans
  • par-5 protein, C elegans
  • par-6 protein, C elegans
  • Green Fluorescent Proteins
  • PAR-1 protein, C elegans
  • PAR-3 protein, C elegans
  • Protein-Serine-Threonine Kinases
  • PKC-3 protein
  • Protein Kinase C