Source 1review2021Journal of Biological Chemistry
Toolkit/phototropin
phototropin
Also known as: NPH1, PHOT1, phototropin blue light receptors, phots
Taxonomy: Mechanism Branch / Component. Workflows sit above the mechanism and technique branches rather than replacing them.
Summary
Phototropin is a plant blue-light receptor protein, exemplified by Avena sativa PHOT1/NPH1, that contains two FMN-binding LOV domains and a C-terminal serine/threonine kinase domain. It acts as a light-activated kinase in which LOV2-mediated conformational changes are coupled to kinase activation and signaling.
Usefulness & Problems
Why this is useful
Phototropins are useful as naturally light-responsive signaling modules because they couple blue-light sensing directly to kinase regulation. The literature also states that phototropins have inspired many diverse optogenetic tools, indicating value as templates for engineering light-controlled biological systems.
Source:
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired.
Problem solved
Phototropins help solve the problem of converting UV-A/blue-light input into regulated intracellular signaling through a genetically encoded protein receptor. In engineering contexts, the cited literature supports their relevance for building optogenetic systems that require light-dependent control of protein activity.
Taxonomy & Function
Primary hierarchy
Mechanism Branch
Component: A low-level protein part used inside a larger architecture that realizes a mechanism.
Mechanisms
allosteric switchingautophosphorylationconformational uncagingConformational Uncaginglight-induced conformational uncagingTechniques
Structural CharacterizationTarget processes
signalingInput: Light
Implementation Constraints
The evidence supports that phototropins are multidomain proteins composed of two FMN-binding LOV domains, LOV1 and LOV2, plus a C-terminal serine/threonine kinase domain. Practical use therefore depends on preserving this domain architecture and FMN-dependent photosensory function, but the supplied sources do not specify construct formats, expression systems, or delivery strategies.
High-resolution structural information for phototropins remains difficult to obtain, and this is identified as a major gap for both mechanistic understanding and engineering. The supplied evidence does not provide quantitative performance metrics such as activation kinetics, dynamic range, wavelength specificity beyond blue/UV-A light, or implementation benchmarks in heterologous systems.
Validation
Cell-freeBacteriaMammalianMouseHumanTherapeuticIndep. Replication
Supporting Sources
Source 2primary paper2001New Phytologist
Source 3primary paper2001Proceedings of the National Academy of Sciences
Ranked Claims
Phototropins contain two blue-light-sensing LOV domains, LOV1 and LOV2, together with a C-terminal serine/threonine kinase domain.
Phototropins combine two blue-light-sensing Light-Oxygen-Voltage (LOV) domains (LOV1 and LOV2) and a C-terminal serine/threonine kinase domain, using the LOV domains to control the catalytic activity of the kinase.
Phototropins are light-activated kinases important for plant physiology and have inspired diverse optogenetic tools.
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired.
High-resolution structural information on phototropins remains challenging to obtain and is presented as important for both fundamental understanding and engineering efforts.
the challenges that will have to be overcome to obtain high-resolution structural information on these exciting photoreceptors. Such information will be essential to advancing fundamental understanding of plant physiology while enabling engineering efforts at both the whole plant and molecular levels.
Activation of the LOV2 domain triggers unfolding of alpha helices that communicate the light signal to the kinase domain.
activation of the LOV2 domain triggers the unfolding of alpha helices that communicate the light signal to the kinase domain
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Light exposure is conducive to autophosphorylation of the phototropin protein kinase domain.
Light exposure is conducive to autophosphorylation of the protein kinase domain.
Avena sativa phototropin comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain.
phototropin, which comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain
The observed conformational change is proposed to initiate light-signal transmission through conformational modulation of the protein kinase domain conducive to autophosphorylation of NPH1.
This conformational change is proposed to initiate the transmission of the light signal via conformational modulation of the protein kinase domain conducive to autophosphorylation of NPH1.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry, and phytochrome signalling pathways regulate CHS expression.
Interactions within a network of UV-B, cry and phytochrome signalling pathways regulate CHS expression.
The UV-B and cry1 signalling pathways differ kinetically and pharmacologically in an Arabidopsis cell suspension culture.
Experiments with an Arabidopsis cell suspension culture show that the UV-B and cry1 signalling pathways differ kinetically and pharmacologically.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Specific phytochromes positively control the cry1 pathway via potentiation and coaction effects and negatively regulate the UV-B pathway.
In addition, specific phytochromes positively control the cry1 pathway via distinct potentiation and coaction effects, and negatively regulate the UV-B pathway.
Distinct UV-A/blue cry-mediated and UV-B photoreception systems control CHS expression in Arabidopsis.
Experiments with photoreceptor mutants show that distinct UV-A/blue (cry mediated) and UV-B photoreception systems control CHS expression.
Approval Evidence
3 sources7 linked approval claimsfirst-pass slug phototropin
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired.
Source:
The PHOT1 (NPH1) gene from Avena sativa specifies the blue light receptor for phototropism, phototropin, which comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain.
Source:
The known photoreceptors for UV-A/blue light are cryptochrome (cry)1 and cry2, and the phototropism photoreceptor, phototropin.
Source:
domain architecturesupports
Phototropins contain two blue-light-sensing LOV domains, LOV1 and LOV2, together with a C-terminal serine/threonine kinase domain.
Phototropins combine two blue-light-sensing Light-Oxygen-Voltage (LOV) domains (LOV1 and LOV2) and a C-terminal serine/threonine kinase domain, using the LOV domains to control the catalytic activity of the kinase.
Source:
functional rolesupports
Phototropins are light-activated kinases important for plant physiology and have inspired diverse optogenetic tools.
The phototropins (phots) are light-activated kinases that are critical for plant physiology and the many diverse optogenetic tools that they have inspired.
Source:
knowledge gapsupports
High-resolution structural information on phototropins remains challenging to obtain and is presented as important for both fundamental understanding and engineering efforts.
the challenges that will have to be overcome to obtain high-resolution structural information on these exciting photoreceptors. Such information will be essential to advancing fundamental understanding of plant physiology while enabling engineering efforts at both the whole plant and molecular levels.
Source:
structural modelsupports
Recent SAXS and other biophysical studies of multidomain phototropins from Chlamydomonas and Arabidopsis support models with an extended linear domain arrangement in which the regulatory LOV2 domain contacts the kinase domain N-lobe.
Recent studies have made progress addressing these questions by utilizing small-angle X-ray scattering (SAXS) and other biophysical approaches to study multidomain phots from Chlamydomonas and Arabidopsis, leading to models where the domains have an extended linear arrangement, with the regulatory LOV2 domain contacting the kinase domain N-lobe.
Source:
activity regulationsupports
Light exposure is conducive to autophosphorylation of the phototropin protein kinase domain.
Light exposure is conducive to autophosphorylation of the protein kinase domain.
Source:
compositionsupports
Avena sativa phototropin comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain.
phototropin, which comprises two FMN-binding LOV domains and a serine/threonine protein kinase domain
Source:
mechanistic proposalsupports
The observed conformational change is proposed to initiate light-signal transmission through conformational modulation of the protein kinase domain conducive to autophosphorylation of NPH1.
This conformational change is proposed to initiate the transmission of the light signal via conformational modulation of the protein kinase domain conducive to autophosphorylation of NPH1.
Source:
Comparisons
Source-backed strengths
A key strength is the integrated architecture of two LOV photosensory domains with a serine/threonine kinase output domain, enabling direct light-regulated enzymatic signaling. Biophysical studies support a mechanistic model in which LOV2 activation triggers alpha-helical unfolding and communication to the kinase domain, and SAXS-based models from Chlamydomonas and Arabidopsis support an extended multidomain arrangement with LOV2 contacting the kinase N-lobe.
Ranked Citations
- 1.
- 2.