Primary cilia and graded Sonic Hedgehog signaling

Wiley Interdiscip Rev Dev Biol. Sep-Oct 2012;1(5):753-72. doi: 10.1002/wdev.43. Epub 2012 Apr 4.


Cilia are evolutionary-conserved microtubule-containing organelles protruding from the surface of cells. They are classified into two types--primary and motile cilia. Primary cilia are nearly ubiquitous, at least in vertebrate cells, and it has become apparent that they play an essential role in the intracellular transduction of a range of stimuli. Most notable among these is Sonic Hedgehog. In this article we briefly summarize the structure and biogenesis of primary cilia. We discuss the evidence implicating cilia in the transduction of extrinsic signals. We focus on the involvement and molecular mechanism of cilia in signaling by Sonic Hedgehog in embryonic tissues, specifically the neural tube, and we discuss how cilia play an active role in the interpretation of gradients of Sonic Hedgehog (Shh) signaling.

Publication types

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

MeSH terms

  • Animals
  • Cell Movement / genetics
  • Cilia / genetics
  • Cilia / ultrastructure*
  • Hedgehog Proteins / classification
  • Hedgehog Proteins / genetics*
  • Hedgehog Proteins / metabolism
  • Mice
  • Neural Tube / growth & development
  • Neural Tube / metabolism*
  • Signal Transduction*


  • Hedgehog Proteins