G proteins and phototransduction

Annu Rev Physiol. 2002:64:153-87. doi: 10.1146/annurev.physiol.64.082701.102229.


Phototransduction is the process by which a photon of light captured by a molecule of visual pigment generates an electrical response in a photoreceptor cell. Vertebrate rod phototransduction is one of the best-studied G protein signaling pathways. In this pathway the photoreceptor-specific G protein, transducin, mediates between the visual pigment, rhodopsin, and the effector enzyme, cGMP phosphodiesterase. This review focuses on two quantitative features of G protein signaling in phototransduction: signal amplification and response timing. We examine how the interplay between the mechanisms that contribute to amplification and those that govern termination of G protein activity determine the speed and the sensitivity of the cellular response to light.

Publication types

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

MeSH terms

  • Animals
  • GTP-Binding Proteins / physiology*
  • Phosphoric Diester Hydrolases / physiology
  • Transducin / physiology
  • Vision, Ocular / physiology*


  • Phosphoric Diester Hydrolases
  • GTP-Binding Proteins
  • Transducin