The molecular basis of self-avoidance

Annu Rev Neurosci. 2013 Jul 8:36:547-68. doi: 10.1146/annurev-neuro-062111-150414.


Self-avoidance, the tendency of neurites of the same cell to selectively avoid each other, is a property of both vertebrate and invertebrate neurons. In Drosophila, self-avoidance is mediated by a large family of cell recognition molecules of the immunoglobulin superfamily encoded, via alternative splicing, by the Dscam1 locus. Dscam1 promotes self-avoidance in dendrites, axons, and prospective postsynaptic elements. Expression analysis suggests that each neuron expresses a unique combination of isoforms. Identical isoforms on sister neurites exhibit isoform-specific homophilic recognition and elicit repulsion between processes, thereby promoting self-avoidance. Although any isoform can promote self-avoidance, thousands are necessary to ensure that neurites readily discriminate between self and nonself. Recent studies indicate that a large family of cadherins in the mouse, i.e., the clustered protocadherins, functions in an analogous fashion to promote self-avoidance. These studies argue for the evolution of a common molecular strategy for self-avoidance.

Publication types

  • Review

MeSH terms

  • Animals
  • Biological Evolution
  • Cadherins / genetics
  • Cadherins / metabolism
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism*
  • Cell Communication / physiology*
  • Dendrites / physiology
  • Drosophila
  • Drosophila Proteins / genetics
  • Drosophila Proteins / metabolism
  • Immunoglobulins / genetics
  • Immunoglobulins / physiology
  • Neurons / cytology
  • Neurons / physiology*


  • Cadherins
  • Cell Adhesion Molecules
  • Drosophila Proteins
  • Dscam1 protein, Drosophila
  • Immunoglobulins