The vertebrate primary cilium is a sensory organelle

Curr Opin Cell Biol. 2003 Feb;15(1):105-10. doi: 10.1016/s0955-0674(02)00012-1.


The primary cilium is a generally non-motile cilium that occurs singly on most cells in the vertebrate body. The function of this organelle, which has been the subject of much speculation but little experimentation, has been unknown. Recent findings reveal that the primary cilium is an antenna displaying specific receptors and relaying signals from these receptors to the cell body. For example, kidney primary cilia display polycystin-2, which forms part of a Ca2+ channel that initiates a signal that controls cell differentiation and proliferation. Kidney primary cilia also are mechanosensors that, when bent, initiate a Ca2+ signal that spreads throughout the cell and to neighboring cells. Primary cilia on other cell types specifically display different receptors, including those for somatostatin and serotonin.

Publication types

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

MeSH terms

  • Animals
  • Calcium Channels / metabolism
  • Cell Membrane / metabolism*
  • Cell Membrane / ultrastructure
  • Cilia / metabolism*
  • Cilia / ultrastructure
  • Eukaryotic Cells / metabolism*
  • Eukaryotic Cells / ultrastructure
  • Humans
  • Kidney / metabolism
  • Kidney / ultrastructure
  • Membrane Proteins / metabolism
  • Receptors, Cell Surface / metabolism*
  • Receptors, Cell Surface / ultrastructure
  • Signal Transduction / physiology*
  • TRPP Cation Channels


  • Calcium Channels
  • Membrane Proteins
  • Receptors, Cell Surface
  • TRPP Cation Channels
  • polycystic kidney disease 2 protein