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Cited by 405Light effects on plantsPlant Molecular Biology ResearchPhotosynthetic Processes and Mechanisms

Cellular and Subcellular Localization of Phototropin 1

Open access
Sakamoto, Koji, Briggs, Winslow R.·2002·The Plant Cell
DOI 10.1105/tpc.003293PMC PMC151461
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Abstract

Phototropin 1 (phot1) is a Ser/Thr photoreceptor kinase that binds two molecules of flavin mononucleotide as its chromophores and undergoes autophosphorylation in response to blue light. Phot1 is plasma membrane associated and, as with phot2, has been shown to function as a photoreceptor for phototropism, blue light-induced chloroplast movement, and blue light-induced stomatal opening. Phot1 likely also plays a redundant role with phot2 in regulating the rate of leaf expansion. Understanding the mechanism(s) by which phot1 initiates these four different responses requires, at minimum, knowledge of where the photoreceptor is located. Therefore, we transformed a phot1 null mutant of Arabidopsis with a construct encoding translationally fused phot1-green fluorescent protein (GFP) under the control of the endogenous PHOT1 promoter and investigated its cellular and subcellular distribution. This PHOT1-GFP construct complements the mutant phenotype, restoring second positive curvature. Phot1 is expressed strongly in dividing and elongating cortical cells in the apical hook and in the root elongation zone in etiolated seedlings. It is localized evenly to the plasma membrane region in epidermal cells but is confined largely to the plasma membrane region of the transverse cell walls in the cortical cells of both root and hypocotyl. It is found at both apical and basal ends of these cortical cells. In light-grown plants, phot1-GFP is localized largely in the plasma membrane regions adjacent to apical and basal cell end walls in the elongating inflorescence stem, where the photoreceptor is expressed strongly in the vascular parenchyma and leaf vein parenchyma. Phot1 also is localized to the plasma membrane region of leaf epidermal cells, mesophyll cells, and guard cells, where its distribution is uniform. Although phot1 is localized consistently to the plasma membrane region in etiolated seedlings, a fraction becomes released to the cytoplasm in response to blue light. Possible relationships between observed phot1 distribution and the various physiological responses activated by blue light are discussed.

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Crossref · 10.1105/tpc.003293

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  • Although phot1 and phot2 do not possess a transmembrane domain, they localize to the inner side of the cytoplasmic membrane in the dark.

    “Although phot1 and phot2 do not possess a transmembrane domain, they localize to the inner side of the cytoplasmic membrane in the dark (Sakamoto and Briggs, 2002; Kong et al., 2006).”

    From The action of enhancing weak light capture via phototropic growth and chloroplast movement in plants (2022) · cites this paper as Sakamoto and Briggs, 2002

    The Introduction (page not provided) says phot1 has no obvious membrane-spanning domain and is associated with the inner surface of the plasma membrane in etiolated seedlings. It says only that phot2 activity is associated with a membrane fraction; phot2 localization to the plasma membrane is described as likely, not established. The claim therefore overstates what this paper supports about phot2. (LLM, conf=0.88)

    Experimental — accuracy not yet measured

  • Under blue light irradiation, part of PHOT1 detaches from the cell membrane and disperses in the cytoplasm, whereas some PHOT2 proteins can be coupled to the Golgi apparatus.

    “Under blue light irradiation, part of the PHOT1 protein detaches from the cell membrane and disperses in the cytoplasm, in contrast, some PHOT2 proteins can be coupled to the Golgi apparatus (Sakamoto and Briggs, 2002; Kong et al., 2006; Wan et al., 2008).”

    From The action of enhancing weak light capture via phototropic growth and chloroplast movement in plants (2022) · cites this paper as Sakamoto and Briggs, 2002

    The paper’s opening summary and discussion (page numbers not supplied) report that a fraction of phot1 moves from the plasma-membrane region into the cytoplasm in response to blue light. They do not support the sentence’s phot2–Golgi claim; the paper says comparable studies of phot2 localization were still in progress. (LLM, conf=0.90)

    Experimental — accuracy not yet measured

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Research works printed but not linked: 4

  1. Briggs, W.R., and Christie, J.M. (2002). Phototropin 1 and phototropin2: Two versatile plant blue-light receptors. Trends Plant Sci. 7, 204–210. [DOI] [PubMed] [Google Scholar]
  2. Jarillo, J.A., Ahmad, M., and Cashmore, A.R. (1998). NPL1 (accession No. AF053941): A second member of the NPH serine/threonine kinase family of Arabidopsis. Plant Physiol. 117, 719. [Google Scholar]
  3. Murashige, T., and Skoog, F. (1962). A revised medium for rapid growth and bioassays with tobacco tissue culture. Physiol. Plant. 15, 473–497. [Google Scholar]
  4. Schroeder, J.I., Allen, G.J., Hugouvieux, V., Kwak, J.M., and Waner, D. (2001). Guard cell signal transduction. Annu. Rev. Plant Physiol. Plant Mol. Biol. 52, 627–658. [DOI] [PubMed] [Google Scholar]

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Authors
Sakamoto, K., & Briggs, W. R.
Affiliations
Carnegie Institution for Science (US)
ORCID
Sakamoto, Koji
Venue
The Plant Cell
Publisher
Oxford University Press (OUP)
Published
2002-08
Volume
14
Issue
8
Pages
1723-1735
ISSN
  • 1040-4651 (ISSN-L)
  • 1532-298X
DOI
10.1105/tpc.003293
PMC
PMC151461
OpenAlex
W2159183165
Cited by
405
References
58
Citations by year
2026: 4 · 2025: 5 · 2024: 14 · 2023: 10 · 2022: 15 · 2021: 12 · 2020: 16 · 2019: 10 · 2018: 12 · 2017: 14 · 2016: 14 · 2015: 15 · 2014: 20 · 2013: 21 · 2012: 28
FWCI
23.65
Type
journal article
Language
en
Open access
Licence
aspb.org/publications/aspb-journals/open-articles (vor, 365 d)
Locations
  • The Plant Cell (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
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 › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Photosynthetic Processes and Mechanisms
Keywords
phototropin 1, subcellular localization, plasma membrane, blue light photoreception, phototropism, phot2, chloroplast movement, stomatal opening, leaf expansion, cortical cells, apical hook, root elongation zone, guard cells, vascular parenchyma, Arabidopsis thaliana
MeSH terms
Cell Membrane, Chloroplasts, Eye Proteins, Flavoproteins, Luminescent Proteins, Mutation, Phosphoproteins, Phosphorylation, Plasmids, Promoter Regions, Genetic, Immunoblotting, Protein Serine-Threonine Kinases, Arabidopsis, Photoreceptor Cells, Invertebrate, Gene Expression Regulation, Plant, Plant Leaves, Plant Roots, Phototropism, Hypocotyl, Plant Stems, Microscopy, Confocal, Plant Epidermis, Arabidopsis Proteins, Drosophila Proteins, Plants, Genetically Modified, Receptors, G-Protein-Coupled, Green Fluorescent Proteins, Cryptochromes

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