Phototropin blue-light receptors

Annu Rev Plant Biol. 2007;58:21-45. doi: 10.1146/annurev.arplant.58.032806.103951.


Phototropins are blue-light receptors controlling a range of responses that serve to optimize the photosynthetic efficiency of plants. These include phototropism, light-induced stomatal opening, and chloroplast movements in response to changes in light intensity. Since the isolation of the Arabidopsis PHOT1 gene in 1997, phototropins have been identified in ferns and mosses where their physiological functions appear to be conserved. Arabidopsis contains two phototropins, phot1 and phot2, that exhibit overlapping functions in addition to having unique physiological roles. Phototropins are light-activated serine/threonine protein kinases. Light sensing by the phototropins is mediated by a repeated motif at the N-terminal region of the protein known as the LOV domain. Photoexcitation of the LOV domain results in receptor autophosphorylation and an initiation of phototropin signaling. Here we summarize the photochemical and biochemical events underlying phototropin activation in addition to the current knowledge of the molecular mechanisms associated with photoreceptor signaling.

Publication types

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

MeSH terms

  • Calcium / metabolism
  • Chloroplasts / metabolism
  • Hypocotyl / growth & development
  • Hypocotyl / metabolism
  • Hypocotyl / radiation effects
  • Models, Molecular
  • Phosphorylation
  • Photosynthetic Reaction Center Complex Proteins / chemistry
  • Photosynthetic Reaction Center Complex Proteins / physiology*
  • Phototropism*
  • Plant Development
  • Plant Proteins / chemistry
  • Plant Proteins / physiology*
  • Plants / metabolism*
  • Plants / radiation effects
  • Protein Structure, Tertiary / physiology
  • Protein-Serine-Threonine Kinases / chemistry
  • Protein-Serine-Threonine Kinases / physiology*
  • Signal Transduction


  • Photosynthetic Reaction Center Complex Proteins
  • Plant Proteins
  • Protein-Serine-Threonine Kinases
  • Calcium