PLR-1, a putative E3 ubiquitin ligase, controls cell polarity and axonal extensions in C. elegans

Dev Biol. 2015 Feb 1;398(1):44-56. doi: 10.1016/j.ydbio.2014.11.008. Epub 2014 Nov 20.


During embryonic development neurons differentiate and extend axons and dendrites that have to reach their appropriate targets. In Caenorhabditis elegans the AVG neuron is the first neuron to extend an axon during the establishment of the ventral nerve cord, the major longitudinal axon tract in the animal. In genetic screens we isolated alleles of plr-1, which caused polarity reversals of the AVG neuron as well as outgrowth and navigation defects of the AVG axon. In addition plr-1 mutants show outgrowth defects in several other classes of neurons as well as the posterior excretory canals. plr-1 is predicted to encode a transmembrane E3 ubiquitin ligase and is widely expressed in the animal including the AVG neuron and the excretory cell. plr-1 has recently been shown to negatively regulate Wnt signalling by removing Wnt receptors from the cell surface. We observed that mutations in a gene reducing Wnt signalling as well as mutations in unc-53/NAV2 and unc-73/Trio suppress the AVG polarity defects in plr-1 mutants, but not the defects seen in other cells. This places plr-1 in a Wnt regulation pathway, but also suggests that plr-1 has Wnt independent functions and interacts with unc-53 and unc-73 to control cell polarity.

Keywords: AVG; Axon guidance; Axon navigation; C. elegans; Cell polarity; E3 ligase; Nervous system; Neuron; Neuronal development; Pioneer; Wnt.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alleles
  • Amino Acid Sequence
  • Animals
  • Axons / physiology*
  • Caenorhabditis elegans / enzymology
  • Caenorhabditis elegans / growth & development*
  • Caenorhabditis elegans Proteins / metabolism
  • Caenorhabditis elegans Proteins / physiology*
  • Cell Membrane / metabolism
  • Cell Movement
  • Cell Polarity*
  • Gene Expression Regulation, Developmental*
  • Green Fluorescent Proteins / metabolism
  • Microfilament Proteins / metabolism
  • Molecular Sequence Data
  • Nerve Tissue Proteins / metabolism
  • Neurons / metabolism
  • Phenotype
  • Protein Structure, Tertiary
  • Signal Transduction
  • Ubiquitin-Protein Ligases / physiology*
  • Wnt Proteins / metabolism


  • Caenorhabditis elegans Proteins
  • Microfilament Proteins
  • Nerve Tissue Proteins
  • UNC-53 protein, C elegans
  • UNC-73 protein, C elegans
  • Wnt Proteins
  • Green Fluorescent Proteins
  • PLR-1 protein, C elegans
  • Ubiquitin-Protein Ligases