C. elegans phototransduction requires a G protein-dependent cGMP pathway and a taste receptor homolog

Nat Neurosci. 2010 Jun;13(6):715-22. doi: 10.1038/nn.2540. Epub 2010 May 2.


The eyeless animal C. elegans is able to sense light and engages in phototaxis behavior that is mediated by photoreceptor cells. However, the molecular and cellular mechanisms underlying phototransduction in C. elegans remain largely unclear. By recording the photoreceptor neuron ASJ in wild-type and various mutant worms, we found that phototransduction in ASJ is a G protein-mediated process and requires membrane-associated guanylate cyclases, but not typical phosphodiesterases. In addition, we found that C. elegans phototransduction requires LITE-1, a candidate photoreceptor protein known to be a member of the invertebrate taste receptor family. Our genetic, pharmacological and electrophysiological data suggest a model in which LITE-1 transduces light signals in ASJ via G protein signaling, which leads to upregulation of the second messenger cGMP, followed by opening of cGMP-sensitive CNG channels and stimulation of photoreceptor cells. Our results identify a phototransduction cascade in C. elegans and implicate the function of a 'taste receptor' in phototransduction.

Publication types

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

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Caenorhabditis elegans
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cyclic GMP / metabolism*
  • Cyclic Nucleotide-Gated Cation Channels / metabolism
  • GTP-Binding Proteins / metabolism*
  • Guanylate Cyclase / metabolism
  • Light Signal Transduction / physiology*
  • Membrane Potentials / physiology
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism*
  • Models, Neurological
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Neurons / physiology
  • Phosphoric Diester Hydrolases / metabolism
  • Photic Stimulation
  • Photoreceptor Cells, Invertebrate / physiology*
  • Signal Transduction
  • Up-Regulation


  • Caenorhabditis elegans Proteins
  • Cyclic Nucleotide-Gated Cation Channels
  • Membrane Proteins
  • Nerve Tissue Proteins
  • lite-1 protein, C elegans
  • Phosphoric Diester Hydrolases
  • GTP-Binding Proteins
  • Guanylate Cyclase
  • Cyclic GMP