Arabidopsis ROOT PHOTOTROPISM2 Is a Light-Dependent Dynamic Modulator of Phototropin1
Open accessPublished version of a preprint
Abstract
) blue light photoreceptor phototropin1 (phot1) is a blue light-activated Ser/Thr protein kinase that mediates various light responses, including phototropism. The function of phot1 in hypocotyl phototropism is dependent on the light induction of ROOT PHOTOTROPISM2 (RPT2) proteins within a broad range of blue light intensities. It is not yet known however how RPT2 contributes to the photosensory adaptation of phot1 to high intensity blue light and the phototropic responses under bright light conditions. We show that RPT2 suppresses the activity of phot1 and demonstrate that RPT2 binds to the PHOT1 light, oxygen or voltage sensing1 (LOV1) domain that is required for its high photosensitivity. Our biochemical analyses revealed that RPT2 inhibits autophosphorylation of phot1, suggesting that it suppresses the photosensitivity and/or kinase activity of phot1 through the inhibition of LOV1 function. We found that RPT2 proteins are degraded via a ubiquitin-proteasome pathway when phot1 is inactive and are stabilized under blue light in a phot1-dependent manner. We propose that RPT2 is a molecular rheostat that maintains a moderate activation level of phot1 under any light intensity conditions.
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RPT2 may play a key role in cross-regulation of phototropism and chloroplast movement.
“Therefore, RPT2 may play a key role in cross-regulation of phototropism and chloroplast movement.”
From The action of enhancing weak light capture via phototropic growth and chloroplast movement in plants (2022) · cites this paper as Kimura et al., 2020
The Discussion (page unavailable) supports RPT2’s role in phototropism and says that NCH1 functions in the chloroplast accumulation response in parallel with RPT2. It hypothesizes a shared effect on phot2, but does not establish that RPT2 cross-regulates phototropism and chloroplast movement or plays a key role in doing so. (LLM, conf=0.81)
Experimental — accuracy not yet measuredThe probable mechanism by which RPT2 maintains a moderate activation level in a phot1-dependent manner is to adapt to different light intensities.
“In plant, the probable mechanism of RPT2 maintains a moderate activation level in a phot1 dependent manner is to adapt different light intensities (Kimura et al., 2020).”
From The action of enhancing weak light capture via phototropic growth and chloroplast movement in plants (2022) · cites this paper as Kimura et al., 2020
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References 49 · Cited by 22
Research works printed but not linked: 3
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- Authors
- Kimura, T., Tsuchida-Mayama, T., Imai, H., Okajima, K., Ito, K., & Sakai, T.
- Affiliations
- Niigata University (JP)
- RIKEN Plant Science Center, Yokohama, Kanagawa 230-0045, Japan
- Japan Society for the Promotion of Science (JP)
- Keio University (JP)
- Corresponding author
- Sakai, Tatsuya
- Venue
- The Plant Cell
- Publisher
- Oxford University Press (OUP)
- Published
- 2020-03-25
- Volume
- 32
- Issue
- 6
- Pages
- 2004-2019
- ISSN
- 1040-4651 (ISSN-L)
- 1532-298X
- PMC
- PMC7268816
- OpenAlex
- W3013529447
- Cited by
- 22
- References
- 49
- Citations by year
- 2026: 2 · 2025: 7 · 2024: 2 · 2023: 3 · 2022: 2 · 2021: 6
- FWCI
- 1.78
- Type
- journal article
- Language
- en
- Open access
- green
- doi.org
- Locations
- The Plant Cell (publishedVersion)
- bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Funders
- Japan Society for the Promotion of Science (22570058, 25120710, 16H01231, 17H03694, 18K19329)
- Topics
- Life Sciences › Agricultural and Biological Sciences › Plant Science › Light effects on plants
- Life Sciences › Agricultural and Biological Sciences › Plant Science › Plant Molecular Biology Research
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Photoreceptor and optogenetics research
- Keywords
- Rpt2, blue light photoreception, phototropism, hypocotyl, ubiquitin-proteasome degradation, protein stability, Arabidopsis thaliana, light intensity
- MeSH terms
- DNA-Binding Proteins, Protein Serine-Threonine Kinases, Arabidopsis, Arabidopsis Proteins
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