Phototropin blue-light receptors.

  title={Phototropin blue-light receptors.},
  author={John M. Christie},
  journal={Annual review of plant biology},
  • J. Christie
  • Published 1 May 2007
  • Biology, Environmental Science
  • Annual review of plant biology
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… 

Figures from this paper

Molecular mechanism of phototropin light signaling

The combined analysis of spectroscopy and STK activity assay in Arabidopsis phots suggests that the decay speed of the photo-intermediate S390 in LOV2 is one of the factors contributing to light sensitive kinase activity.

Reconstitution of an Initial Step of Phototropin Signaling in Stomatal Guard Cells.

The results provide the first reconstitution of a primary step of Phototropin signaling in vitro using a physiological substrate of phototropin, the BLUS1 kinase of guard cells, and a clue for understanding the molecular nature of this process.

Phototropin Receptor Kinase Activation by Blue Light

Although phototropins possess two LOV photosensors, recent biophysical and structure-function analyses clearly indicate that the LOV2 domain plays a predominant role in regulating phototropin kinase activity owing to specific protein changes that occur in response to Lov2 photoexcitation.

New light on the mechanism of phototransduction in phototropin.

A structural model of how Lov1 and LOV2 domains interact and regulate the full-length phototropin from Chlamydomonas reinhardtii is proposed, which provides a rationale for how LOV photosensor proteins function and contributes to the optimal design of optogenetic tools based on LOV domains.

Structure-function analysis of phototropin receptor kinases

  • M. Jones
  • Biology, Environmental Science
  • 2008
A baculovirus/insect cell expression system is used to further characterise the mode of phototropin autophosphorylation and the functionality of a mutated Phototropin 1 which demonstrates increased autoph phosphorylation activity in this system is assessed in planta using transgenic Arabidopsis.

Regulation of Phototropic Signaling in Arabidopsis via Phosphorylation State Changes in the Phototropin 1-interacting Protein NPH3*

It is shown that, in dark-grown seedlings, NPH3 exists as a phosphorylated protein and that BL stimulates its dephosphorylation, and suggests that this post-translational modification represents a crucial event in phot1-dependent phototropism.

Phototropin signaling and stomatal opening as a model case.

Arabidopsis ROOT PHOTOTROPISM2 Is a Light-Dependent Dynamic Modulator of Phototropin1

The biochemical analyses revealed that RPT2 inhibits autophosphorylation of phot1, suggesting that it suppresses the photosensitivity and/or kinase activity ofPhot1 through the inhibition of LOV1 function, and it is proposed that R PT2 is a molecular rheostat that maintains a moderate activation level of phot 1 under any light intensity conditions.

Blue light-induced autophosphorylation of phototropin is a primary step for signaling

Phototropins are autophosphorylating protein kinases of plant-specific blue light receptors. They regulate various blue light responses, including phototropism, chloroplast movements, hypocotyl



Phototropins 1 and 2: versatile plant blue-light receptors.

Phototropin and light-signaling in phototropism.

Blue light activates calcium-permeable channels in Arabidopsis mesophyll cells via the phototropin signaling pathway

It is concluded that blue light triggers calcium fluxes via the phototropin-activated calcium-permeable channel on illumination with blue light, but not red light, voltage-dependent and calcium- permeable channels activate in the plasma membrane of mesophyll cells.

Responses of ferns to red light are mediated by an unconventional photoreceptor

The fern Adiantum capillus-veneris has an unconventional photoreceptor, phy tochrome 3 (phy3), which is a chimaera of the red/far-red light receptor phytochrome and phototropin, which greatly enhances the sensitivity to white light in orienting leaves and chloroplasts, and PHY3 homologues exist among various fern species.

Photochemical and mutational analysis of the FMN-binding domains of the plant blue light receptor, phototropin.

It is demonstrated that the LOV domains of Avena sativa phototropin undergo a self-contained photocycle characterized by a loss of blue light absorbance in response to light and a spontaneous recovery of the blue light-absorbing form in the dark.

Primary reactions of the LOV2 domain of phototropin, a plant blue-light photoreceptor.

The results indicate that the majority of the FMN triplets in the LOV2 domain exist in the protonated form, and a reaction mechanism that involves excited-state proton transfer from the sulfhydryl group of the conserved cysteine to the N5 atom of FMN is proposed.

Primary Processes During the Light‐signal Transduction of Phototropin

The photoregulation mechanism of phototropin kinase is reviewed and discussed in reference to the regulation mechanism of protein kinase A, which it resembles.

Blue light-induced association of phototropin 2 with the Golgi apparatus.

The BL-induced Golgi localization of phot2 may be one of important signaling steps in the phot2 signal transduction pathway.

RPT2: A Signal Transducer of the Phototropic Response in Arabidopsis

A genetic model of the signaling pathways that induce the phototropic response in Arabidopsis is proposed and a newly isolated gene, RPT2, controls one of these pathways.

Stimulation of the blue light phototropic receptor NPH1 causes a transient increase in cytosolic Ca2+.

Blue light treatment of cry1, cry2, and nph1 mutants showed that NPH1, which regulates phototropism, is largely responsible for the Ca2+ transient, raising the possibility that physiological responses regulated by N PH1, such as phototropic sensitivity, may be transduced through cytosolic Ca2+.