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Péter C, Nagy F, Viczián A. SUMOylation of different targets fine-tunes phytochrome signaling. THE NEW PHYTOLOGIST 2021; 232:1201-1211. [PMID: 34289130 DOI: 10.1111/nph.17634] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 07/12/2021] [Indexed: 06/13/2023]
Abstract
Plants monitor their surrounding ambient light environment by specialized photoreceptor proteins. Among them, phytochromes monitor red and far-red light. These molecules perceive photons, undergo a conformational change, and regulate diverse light signaling pathways, resulting in the mediation of key developmental and growth responses throughout the whole life of plants. Posttranslational modifications of the photoreceptors and their signaling partners may modify their function. For example, the regulatory role of phosphorylation has been investigated for decades by using different methodological approaches. In the past few years, a set of studies revealed that ubiquitin-like short protein molecules, called small ubiquitin-like modifiers (SUMOs) are attached reversibly to different members of phytochrome signaling pathways, including phytochrome B, the dominant receptor of red light signaling. Furthermore, SUMO attachment modifies the action of the target proteins, leading to altered light signaling and photomorphogenesis. This review summarizes recent results regarding SUMOylation of various target proteins, the regulation of their SUMOylation level, and the physiological consequences of SUMO attachment. Potential future research directions are also discussed.
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Affiliation(s)
- Csaba Péter
- Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
- Doctoral School in Biology, Faculty of Science and Informatics, University of Szeged, Szeged, H-6726, Hungary
| | - Ferenc Nagy
- Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
| | - András Viczián
- Laboratory of Photo and Chronobiology, Institute of Plant Biology, Biological Research Centre, Eötvös Loránd Research Network (ELKH), Szeged, H-6726, Hungary
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2
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A LexA-based yeast two-hybrid system for studying light-switchable interactions of phytochromes with their interacting partners. ABIOTECH 2021; 2:105-116. [PMID: 36304755 PMCID: PMC9590525 DOI: 10.1007/s42994-021-00034-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 02/01/2021] [Indexed: 12/26/2022]
Abstract
Phytochromes are a family of photoreceptors in plants that perceive the red (R) and far-red (FR) components of their light environment. Phytochromes exist in vivo in two forms, the inactive Pr form and the active Pfr form, that are interconvertible by treatments with R or FR light. It is believed that phytochromes transduce light signals by interacting with their signaling partners. A GAL4-based light-switchable yeast two-hybrid (Y2H) system was developed two decades ago and has been successfully employed in many studies to determine phytochrome interactions with their signaling components. However, several pairs of interactions between phytochromes and their interactors, such as the phyA-COP1 and phyA-TZP interactions, were demonstrated by other assay systems but were not detected by this GAL4 Y2H system. Here, we report a modified LexA Y2H system, in which the LexA DNA-binding domain is fused to the C-terminus of a phytochrome protein. The conformational changes of phytochromes in response to R and FR light are achieved in yeast cells by exogenously supplying phycocyanobilin (PCB) extracted from Spirulina. The well-defined interaction pairs, including phyA-FHY1 and phyB-PIFs, are well reproducible in this system. Moreover, we show that our system is successful in detecting the phyA-COP1 and phyA-TZP interactions. Together, our study provides an alternative Y2H system that is highly sensitive and reproducible for detecting light-switchable interactions of phytochromes with their interacting partners. Supplementary Information The online version contains supplementary material available at 10.1007/s42994-021-00034-5.
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3
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Song B, Zhao H, Dong K, Wang M, Wu S, Li S, Wang Y, Chen P, Jiang L, Tao Y. Phytochrome A inhibits shade avoidance responses under strong shade through repressing the brassinosteroid pathway in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:1520-1534. [PMID: 33037720 DOI: 10.1111/tpj.15018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
In dense canopy, a reduction in red to far-red (R/FR) light ratio triggers shade avoidance responses (SARs) in Arabidopsis thaliana, a shade avoiding plant. Two red/far-red (R/FR) light photoreceptors, PHYB and PHYA, were reported to be key negative regulators of the SARs. PHYB represses the SARs under normal light conditions; however, the role of PHYA in the SARs remains elusive. We set up two shade conditions: Shade and strong Shade (s-Shade) with different R/FR ratios (0.7 and 0.1), which allowed us to observe phenotypes dominated by PHYB- and PHYA-mediated pathway, respectively. By comparing the hypocotyl growth under these two conditions with time, we found PHYA was predominantly activated in the s-Shade after prolonged shade treatment. We further showed that under s-Shade, PHYA inhibits hypocotyl elongation partially through repressing the brassinosteroid (BR) pathway. COP1 and PIF4,5 act downstream of PHYA. After prolonged shade treatment, the nuclear localization of COP1 was reduced, while the PIF4 protein level was much lower in the s-Shade than that in Shade. Both changes occurred in a PHYA-dependent manner. We propose that under deep canopy, the R/FR ratio is extremely low, which promotes the nuclear accumulation of PHYA. Activated PHYA reduces COP1 nuclear speckle, which may lead to changes of downstream targets, such as PIF4,5 and HY5. Together, these proteins regulate the BR pathway through modulating BES1/BZR1 and the expression of BR biosynthesis and BR target genes.
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Affiliation(s)
- Bin Song
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Hongli Zhao
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Kangmei Dong
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Meiling Wang
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Shujuan Wu
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Si Li
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Yuxiang Wang
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Peirui Chen
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Liangrong Jiang
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
| | - Yi Tao
- Xiamen Plant Genetics Key Laboratory and State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, 361102, China
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Kahle N, Sheerin DJ, Fischbach P, Koch LA, Schwenk P, Lambert D, Rodriguez R, Kerner K, Hoecker U, Zurbriggen MD, Hiltbrunner A. COLD REGULATED 27 and 28 are targets of CONSTITUTIVELY PHOTOMORPHOGENIC 1 and negatively affect phytochrome B signalling. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 104:1038-1053. [PMID: 32890447 DOI: 10.1111/tpj.14979] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 07/31/2020] [Accepted: 08/10/2020] [Indexed: 05/23/2023]
Abstract
Phytochromes are red/far-red light receptors in plants involved in the regulation of growth and development. Phytochromes can sense the light environment and contribute to measuring day length; thereby, they allow plants to respond and adapt to changes in the ambient environment. Two well-characterized signalling pathways act downstream of phytochromes and link light perception to the regulation of gene expression. The CONSTITUTIVELY PHOTOMORPHOGENIC 1/SUPPRESSOR OF PHYA-105 (COP1/SPA) E3 ubiquitin ligase complex and the PHYTOCHROME INTERACTING FACTORs (PIFs) are key components of these pathways and repress light responses in the dark. In light-grown seedlings, phytochromes inhibit COP1/SPA and PIF activity and thereby promote light signalling. In a yeast-two-hybrid screen for proteins binding to light-activated phytochromes, we identified COLD-REGULATED GENE 27 (COR27). COR27 and its homologue COR28 bind to phyA and phyB, the two primary phytochromes in seed plants. COR27 and COR28 have been described previously with regard to a function in the regulation of freezing tolerance, flowering and the circadian clock. Here, we show that COR27 and COR28 repress early seedling development in blue, far-red and in particular red light. COR27 and COR28 contain a conserved Val-Pro (VP)-peptide motif, which mediates binding to the COP1/SPA complex. COR27 and COR28 are targeted for degradation by COP1/SPA and mutant versions with a VP to AA amino acid substitution in the VP-peptide motif are stabilized. Overall, our data suggest that COR27 and COR28 accumulate in light but act as negative regulators of light signalling during early seedling development, thereby preventing an exaggerated response to light.
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Affiliation(s)
- Nikolai Kahle
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
| | - David J Sheerin
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
| | - Patrick Fischbach
- Institute of Synthetic Biology and CEPLAS, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
| | - Leonie-Alexa Koch
- Institute of Synthetic Biology and CEPLAS, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
| | - Philipp Schwenk
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, Freiburg, 79104, Germany
| | - Dorothee Lambert
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
| | - Ryan Rodriguez
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
| | - Konstantin Kerner
- Institute for Plant Sciences, University of Cologne, Cologne, 50674, Germany
| | - Ute Hoecker
- Institute for Plant Sciences, University of Cologne, Cologne, 50674, Germany
| | - Matias D Zurbriggen
- Institute of Synthetic Biology and CEPLAS, Heinrich Heine University Düsseldorf, Düsseldorf, 40225, Germany
| | - Andreas Hiltbrunner
- Institute of Biology II, Faculty of Biology, University of Freiburg, Freiburg, 79104, Germany
- Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, 79104, Germany
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5
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Ponnu J. Molecular mechanisms suppressing COP1/SPA E3 ubiquitin ligase activity in blue light. PHYSIOLOGIA PLANTARUM 2020; 169:418-429. [PMID: 32248530 DOI: 10.1111/ppl.13103] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 03/19/2020] [Accepted: 03/27/2020] [Indexed: 05/23/2023]
Abstract
Arabidopsis CONSTITUTIVE PHOTOMORPHOGENIC1/SUPPRESSOR OF PHYA-105 (COP1/SPA) is an E3 ubiquitin ligase complex that prevents photomorphogenesis in darkness by ubiquitinating and subsequently degrading light-responsive transcription factors. Upon light perception, photoreceptors directly interact with the COP1/SPA complex to suppress its activity. In blue light (450-500 nm of visible spectrum), COP1/SPA activity is inhibited by the cryptochrome photoreceptors (CRY1 and CRY2), FKF1 from the ZEITLUPE family as well as phytochrome A. Together, these photoreceptors regulate vital aspects of plant growth and development from seedling stage to the induction of flowering. This review presents and discusses the recent advances in blue light-mediated suppression of COP1/SPA activity.
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Affiliation(s)
- Jathish Ponnu
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, 50674 Cologne, Germany
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6
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Nagano S, Guan K, Shenkutie SM, Feiler C, Weiss M, Kraskov A, Buhrke D, Hildebrandt P, Hughes J. Structural insights into photoactivation and signalling in plant phytochromes. NATURE PLANTS 2020; 6:581-588. [PMID: 32366982 DOI: 10.1038/s41477-020-0638-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 03/16/2020] [Indexed: 05/11/2023]
Abstract
Plant phytochromes are red/far-red photochromic photoreceptors that act as master regulators of development, controlling the expression of thousands of genes. Here, we describe the crystal structures of four plant phytochrome sensory modules, three at about 2 Å resolution or better, including the first of an A-type phytochrome. Together with extensive spectral data, these structures provide detailed insight into the structure and function of plant phytochromes. In the Pr state, the substitution of phycocyanobilin and phytochromobilin cofactors has no structural effect, nor does the amino-terminal extension play a significant functional role. Our data suggest that the chromophore propionates and especially the phytochrome-specific domain tongue act differently in plant and prokaryotic phytochromes. We find that the photoproduct in period-ARNT-single-minded (PAS)-cGMP-specific phosphodiesterase-adenylyl cyclase-FhlA (GAF) bidomains might represent a novel intermediate between MetaRc and Pfr. We also discuss the possible role of a likely nuclear localization signal specific to and conserved in the phytochrome A lineage.
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Affiliation(s)
- Soshichiro Nagano
- Institut für Pflanzenphysiologie, Justus-Liebig-Universität, Gießen, Germany
| | - Kaoling Guan
- Institut für Pflanzenphysiologie, Justus-Liebig-Universität, Gießen, Germany
| | | | - Christian Feiler
- BESSY II, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Manfred Weiss
- BESSY II, Helmholtz-Zentrum Berlin für Materialien und Energie, Berlin, Germany
| | - Anastasia Kraskov
- Institut für Chemie, Sekr. PC14, Technische Universität, Berlin, Germany
| | - David Buhrke
- Institut für Chemie, Sekr. PC14, Technische Universität, Berlin, Germany
| | - Peter Hildebrandt
- Institut für Chemie, Sekr. PC14, Technische Universität, Berlin, Germany
| | - Jon Hughes
- Institut für Pflanzenphysiologie, Justus-Liebig-Universität, Gießen, Germany.
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Lau K, Podolec R, Chappuis R, Ulm R, Hothorn M. Plant photoreceptors and their signaling components compete for COP1 binding via VP peptide motifs. EMBO J 2019; 38:e102140. [PMID: 31304983 PMCID: PMC6745501 DOI: 10.15252/embj.2019102140] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/29/2019] [Accepted: 06/07/2019] [Indexed: 12/31/2022] Open
Abstract
Plants sense different parts of the sun's light spectrum using distinct photoreceptors, which signal through the E3 ubiquitin ligase COP1. Here, we analyze why many COP1‐interacting transcription factors and photoreceptors harbor sequence‐divergent Val‐Pro (VP) motifs that bind COP1 with different binding affinities. Crystal structures of the VP motifs of the UV‐B photoreceptor UVR8 and the transcription factor HY5 in complex with COP1, quantitative binding assays, and reverse genetic experiments together suggest that UVR8 and HY5 compete for COP1. Photoactivation of UVR8 leads to high‐affinity cooperative binding of its VP motif and its photosensing core to COP1, preventing COP1 binding to its substrate HY5. UVR8–VP motif chimeras suggest that UV‐B signaling specificity resides in the UVR8 photoreceptor core. Different COP1–VP peptide motif complexes highlight sequence fingerprints required for COP1 targeting. The blue‐light photoreceptors CRY1 and CRY2 also compete with transcription factors for COP1 binding using similar VP motifs. Thus, our work reveals that different photoreceptors and their signaling components compete for COP1 via a conserved mechanism to control different light signaling cascades.
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Affiliation(s)
- Kelvin Lau
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Roman Podolec
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Richard Chappuis
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Roman Ulm
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Michael Hothorn
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland
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8
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Podolec R, Ulm R. Photoreceptor-mediated regulation of the COP1/SPA E3 ubiquitin ligase. CURRENT OPINION IN PLANT BIOLOGY 2018; 45:18-25. [PMID: 29775763 DOI: 10.1016/j.pbi.2018.04.018] [Citation(s) in RCA: 149] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/25/2018] [Accepted: 04/29/2018] [Indexed: 05/19/2023]
Abstract
Plants have evolved specific photoreceptors that capture informational cues from sunlight. The phytochrome, cryptochrome, and UVR8 photoreceptors perceive red/far-red, blue/UV-A, and UV-B light, respectively, and control overlapping photomorphogenic responses important for plant growth and development. A major repressor of such photomorphogenic responses is the E3 ubiquitin ligase formed by CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1) and SUPPRESSOR OF PHYA-105 (SPA) proteins, which acts by regulating the stability of photomorphogenesis-promoting transcription factors. The direct interaction of light-activated photoreceptors with the COP1/SPA complex represses its activity via nuclear exclusion of COP1, disruption of the COP1-SPA interaction, and/or SPA protein degradation. This process enables plants to integrate different light signals at the level of the COP1/SPA complex to enact appropriate photomorphogenic responses according to the light environment.
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Affiliation(s)
- Roman Podolec
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland; Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland
| | - Roman Ulm
- Department of Botany and Plant Biology, Section of Biology, Faculty of Sciences, University of Geneva, CH-1211 Geneva 4, Switzerland; Institute of Genetics and Genomics of Geneva (iGE3), University of Geneva, Geneva, Switzerland.
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9
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Biological activity and dimerization state of modified phytochrome A proteins. PLoS One 2017; 12:e0186468. [PMID: 29049346 PMCID: PMC5648194 DOI: 10.1371/journal.pone.0186468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/02/2017] [Indexed: 11/29/2022] Open
Abstract
To assess potential physical interactions of type I phyA with the type II phyB-phyE phytochromes in vivo, transgenes expressing fusion gene forms of phyA were introduced into the Arabidopsis phyA mutant background. When a single c-Myc (myc) epitope is added to either the N- or C-terminus of phyA, the constructs completely complement phyA mutant phenotypes. However, addition of larger tags, such as six consecutive myc epitopes or the yellow fluorescent protein sequence, result in fusion proteins that show reduced activity. All the tagged phyA proteins migrate as dimers on native gels and co-immunoprecipitation reveals no binding interaction of phyA to any of the type II phys in the dark or under continuous far-red light. Dimers of the phyA 1–615 amino acid N-terminal photosensory domain (NphyA), generated in vivo with a yeast GAL4 dimerization domain and attached to a constitutive nuclear localization sequence, are expressed at a low level and, although they cause a cop phenotype in darkness and mediate a very low fluence response to pulses of FR, have no activity under continuous FR. It is concluded that type I phyA in its Pr form is present in plants predominantly or exclusively as a homodimer and does not stably interact with type II phys in a dimer-to-dimer manner. In addition, its activity in mediating response to continuous FR is sensitive to modification of its N- or C-terminus.
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10
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Holtkotte X, Dieterle S, Kokkelink L, Artz O, Leson L, Fittinghoff K, Hayama R, Ahmad M, Hoecker U. Mutations in the N-terminal kinase-like domain of the repressor of photomorphogenesis SPA1 severely impair SPA1 function but not light responsiveness in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:205-218. [PMID: 27310313 DOI: 10.1111/tpj.13241] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/10/2016] [Accepted: 06/10/2016] [Indexed: 05/23/2023]
Abstract
The COP1/SPA complex is an E3 ubiquitin ligase that acts as a key repressor of photomorphogenesis in dark-grown plants. While both COP1 and the four SPA proteins contain coiled-coil and WD-repeat domains, SPA proteins differ from COP1 in carrying an N-terminal kinase-like domain that is not present in COP1. Here, we have analyzed the effects of deletions and missense mutations in the N-terminus of SPA1 when expressed in a spa quadruple mutant background devoid of any other SPA proteins. Deletion of the large N-terminus of SPA1 severely impaired SPA1 activity in transgenic plants with respect to seedling etiolation, leaf expansion and flowering time. This ΔN SPA1 protein showed a strongly reduced affinity for COP1 in vitro and in vivo, indicating that the N-terminus contributes to COP1/SPA complex formation. Deletion of only the highly conserved 95 amino acids of the kinase-like domain did not severely affect SPA1 function nor interactions with COP1 or cryptochromes. In contrast, missense mutations in this part of the kinase-like domain severely abrogated SPA1 function, suggesting an overriding negative effect of these mutations on SPA1 activity. We therefore hypothesize that the sequence of the kinase-like domain has been conserved during evolution because it carries structural information important for the activity of SPA1 in darkness. The N-terminus of SPA1 was not essential for light responsiveness of seedlings, suggesting that photoreceptors can inhibit the COP1/SPA complex in the absence of the SPA1 N-terminal domain. Together, these results uncover an important, but complex role of the SPA1 N-terminus in the suppression of photomorphogenesis.
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Affiliation(s)
- Xu Holtkotte
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Stefan Dieterle
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Leonie Kokkelink
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Oliver Artz
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Lisa Leson
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Kirsten Fittinghoff
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
| | - Ryosuke Hayama
- Max Planck Institute of Plant Breeding Research and Cluster of Excellence on Plant Sciences (CEPLAS), Carl-von-Linné Weg 10, 50829, Cologne, Germany
| | - Margaret Ahmad
- UMR 8256 (B2A) CNRS - UPMC, IBPS, Université Pierre et Marie Curie, Bat C 3éme étage, 9 quai Saint-Bernard, 75252, Paris, Cedex 05, France
| | - Ute Hoecker
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Zülpicher Str. 47b, 50674, Cologne, Germany
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11
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Menon C, Sheerin DJ, Hiltbrunner A. SPA proteins: SPAnning the gap between visible light and gene expression. PLANTA 2016; 244:297-312. [PMID: 27100111 DOI: 10.1007/s00425-016-2509-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2016] [Accepted: 03/26/2016] [Indexed: 05/23/2023]
Abstract
In this review we focus on the role of SPA proteins in light signalling and discuss different aspects, including molecular mechanisms, specificity, and evolution. The ability of plants to perceive and respond to their environment is key to their survival under ever-changing conditions. The abiotic factor light is of particular importance for plants. Light provides plants energy for carbon fixation through photosynthesis, but also is a source of information for the adaptation of growth and development to the environment. Cryptochromes and phytochromes are major photoreceptors involved in control of developmental decisions in response to light cues, including seed germination, seedling de-etiolation, and induction of flowering. The SPA protein family acts in complex with the E3 ubiquitin ligase COP1 to target positive regulators of light responses for degradation by the 26S proteasome to suppress photomorphogenic development in darkness. Light-activated cryptochromes and phytochromes both repress the function of COP1, allowing accumulation of positive photomorphogenic factors in light. In this review, we highlight the role of the SPA proteins in this process and discuss recent advances in understanding how SPAs link light-activation of photoreceptors and downstream signaling.
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Affiliation(s)
- Chiara Menon
- Faculty of Biology, Institute of Biology II, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
- Center for Plant Molecular Biology, University of Tübingen, Auf der Morgenstelle 32, 72076, Tübingen, Germany
| | - David J Sheerin
- Faculty of Biology, Institute of Biology II, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany
| | - Andreas Hiltbrunner
- Faculty of Biology, Institute of Biology II, University of Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany.
- BIOSS Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, 79104, Freiburg, Germany.
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12
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Kaiserli E, Páldi K, O'Donnell L, Batalov O, Pedmale UV, Nusinow DA, Kay SA, Chory J. Integration of Light and Photoperiodic Signaling in Transcriptional Nuclear Foci. Dev Cell 2016; 35:311-21. [PMID: 26555051 DOI: 10.1016/j.devcel.2015.10.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 08/08/2015] [Accepted: 10/09/2015] [Indexed: 10/22/2022]
Abstract
Light regulates major plant developmental transitions by orchestrating a series of nuclear events. This study uncovers the molecular function of the natural variant, TZP (Tandem Zinc-finger-Plus3), as a signal integrator of light and photoperiodic pathways in transcriptional nuclear foci. We report that TZP acts as a positive regulator of photoperiodic flowering via physical interactions with the red-light receptor phytochrome B (phyB). We demonstrate that TZP localizes in dynamic nuclear domains regulated by light quality and photoperiod. This study shows that phyB is indispensable not only for localizing TZP to transcriptionally active nuclear photobodies, but also for recruiting TZP on the promoter of the floral inducer FLOWERING LOCUS T (FT). Our findings signify a unique transcriptional regulatory role to the highly enigmatic plant nuclear photobodies, where TZP directly activates FT gene expression and promotes flowering.
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Affiliation(s)
- Eirini Kaiserli
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA; Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Katalin Páldi
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Liz O'Donnell
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
| | - Olga Batalov
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Ullas V Pedmale
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Dmitri A Nusinow
- Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Steve A Kay
- Center for Chronobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
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13
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Huang H, Alvarez S, Bindbeutel R, Shen Z, Naldrett MJ, Evans BS, Briggs SP, Hicks LM, Kay SA, Nusinow DA. Identification of Evening Complex Associated Proteins in Arabidopsis by Affinity Purification and Mass Spectrometry. Mol Cell Proteomics 2015; 15:201-17. [PMID: 26545401 PMCID: PMC4762519 DOI: 10.1074/mcp.m115.054064] [Citation(s) in RCA: 120] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Indexed: 11/30/2022] Open
Abstract
Many species possess an endogenous circadian clock to synchronize internal physiology with an oscillating external environment. In plants, the circadian clock coordinates growth, metabolism and development over daily and seasonal time scales. Many proteins in the circadian network form oscillating complexes that temporally regulate myriad processes, including signal transduction, transcription, protein degradation and post-translational modification. In Arabidopsis thaliana, a tripartite complex composed of EARLY FLOWERING 4 (ELF4), EARLY FLOWERING 3 (ELF3), and LUX ARRHYTHMO (LUX), named the evening complex, modulates daily rhythms in gene expression and growth through transcriptional regulation. However, little is known about the physical interactions that connect the circadian system to other pathways. We used affinity purification and mass spectrometry (AP-MS) methods to identify proteins that associate with the evening complex in A. thaliana. New connections within the circadian network as well as to light signaling pathways were identified, including linkages between the evening complex, TIMING OF CAB EXPRESSION1 (TOC1), TIME FOR COFFEE (TIC), all phytochromes and TANDEM ZINC KNUCKLE/PLUS3 (TZP). Coupling genetic mutation with affinity purifications tested the roles of phytochrome B (phyB), EARLY FLOWERING 4, and EARLY FLOWERING 3 as nodes connecting the evening complex to clock and light signaling pathways. These experiments establish a hierarchical association between pathways and indicate direct and indirect interactions. Specifically, the results suggested that EARLY FLOWERING 3 and phytochrome B act as hubs connecting the clock and red light signaling pathways. Finally, we characterized a clade of associated nuclear kinases that regulate circadian rhythms, growth, and flowering in A. thaliana. Coupling mass spectrometry and genetics is a powerful method to rapidly and directly identify novel components and connections within and between complex signaling pathways.
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Affiliation(s)
- He Huang
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132
| | - Sophie Alvarez
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132
| | - Rebecca Bindbeutel
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132
| | - Zhouxin Shen
- §University of California San Diego, Division of Biological Sciences, Cell and Developmental Biology Section, 9500 Gilman Drive, La Jolla, California 92093-0116
| | - Michael J Naldrett
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132
| | - Bradley S Evans
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132
| | - Steven P Briggs
- §University of California San Diego, Division of Biological Sciences, Cell and Developmental Biology Section, 9500 Gilman Drive, La Jolla, California 92093-0116
| | - Leslie M Hicks
- ¶The University of North Carolina at Chapel Hill, Department of Chemistry, Chapel Hill, North Carolina 27599
| | - Steve A Kay
- ‖University of Southern California, Molecular and Computational Biology Section, Los Angeles, California 90089
| | - Dmitri A Nusinow
- From the ‡Donald Danforth Plant Science Center, 975 N. Warson Road, St. Louis, Missouri, 63132;
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14
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Chen S, Lory N, Stauber J, Hoecker U. Photoreceptor Specificity in the Light-Induced and COP1-Mediated Rapid Degradation of the Repressor of Photomorphogenesis SPA2 in Arabidopsis. PLoS Genet 2015; 11:e1005516. [PMID: 26368289 PMCID: PMC4569408 DOI: 10.1371/journal.pgen.1005516] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Accepted: 08/19/2015] [Indexed: 11/18/2022] Open
Abstract
The Arabidopsis COP1/SPA E3 ubiquitin ligase is a key negative regulator that represses light signaling in darkness by targeting transcription factors involved in the light response for degradation. The COP1/SPA complex consists of COP1 and members of the four-member SPA protein family (SPA1-SPA4). Genetic analysis indicated that COP1/SPA2 function is particularly strongly repressed by light when compared to complexes carrying the other three SPAs, thereby promoting a light response after exposure of plants to extremely low light. Here, we show that the SPA2 protein is degraded within 5–15 min after exposure of dark-grown seedlings to a pulse of light. Phytochrome photoreceptors are required for the rapid degradation of SPA2 in red, far-red and also in blue light, whereas cryptochromes are not involved in the rapid, blue light-induced reduction in SPA2 protein levels. These results uncover a photoreceptor-specific mechanism of light-induced inhibition of COP1/SPA2 function. Phytochrome A (phyA) is required for the severe blue light responsiveness of spa triple mutants expressing only SPA2, thus confirming the important role of phyA in downregulating SPA2 function in blue light. In blue light, SPA2 forms a complex with cryptochrome 1 (cry1), but not with cryptochrome 2 (cry2) in vivo, indicating that the lack of a rapid blue light response of the SPA2 protein is only in part caused by a failure to interact with cryptochromes. Since SPA1 interacts with both cry1 and cry2, these results provide first molecular evidence that the light-regulation of different SPA proteins diverged during evolution. SPA2 degradation in the light requires COP1 and the COP1-interacting coiled-coil domain of SPA2, supporting that SPA2 is ubiquitinated by COP1. We propose that light perceived by phytochromes causes a switch in the ubiquitination activity of COP1/SPA2 from ubiquitinating downstream substrates to ubiquitinating SPA2, which subsequently causes a repression of COP1/SPA2 function. Plants have evolved photoreceptors that initiate a signaling cascade to adjust growth and development to the ambient light environment. The CUL4-dependent COP1/SPA E3 ubiquitin ligase is a key negative regulator of light signaling whose function is repressed by light. Recent research has identified mechanisms that are common to both phytochrome and cryptochrome photoreceptors. Here, we have identified a mechanism of light-induced COP1/SPA repression that is specific to phytochrome photoreceptors. We show that the SPA2 protein is very rapidly degraded in red, far-red and blue light in a phytochrome-dependent fashion. We further show that SPA2 degradation in the light depends on COP1 and on the interaction of SPA2 with COP1. Hence, our results suggest a light-induced degradation of SPA2, but not of COP1, by the COP1/SPA2 ubiquitin ligase. The human ortholog of COP1, which functions without the plant-specific SPA proteins, is known to be regulated by autodegradation following DNA damage. Hence, autodegradation of components of this E3 ligase is a regulatory mechanism used in both humans and plants.
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Affiliation(s)
- Song Chen
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Cologne, Germany
| | - Niels Lory
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Cologne, Germany
| | - Johannes Stauber
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Cologne, Germany
| | - Ute Hoecker
- Botanical Institute and Cluster of Excellence on Plant Sciences (CEPLAS), Biocenter, University of Cologne, Cologne, Germany
- * E-mail:
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15
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Lu XD, Zhou CM, Xu PB, Luo Q, Lian HL, Yang HQ. Red-light-dependent interaction of phyB with SPA1 promotes COP1-SPA1 dissociation and photomorphogenic development in Arabidopsis. MOLECULAR PLANT 2015; 8:467-78. [PMID: 25744387 DOI: 10.1016/j.molp.2014.11.025] [Citation(s) in RCA: 125] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 05/18/2023]
Abstract
Arabidopsis phytochromes (phyA-phyE) are photoreceptors dedicated to sensing red/far-red light. Phytochromes promote photomorphogenic developments upon light irradiation via a signaling pathway that involves rapid degradation of PIFs (PHYTOCHROME INTERACTING FACTORS) and suppression of COP1 (CONSTITUTIVE PHOTOMORPHOGENIC 1) nuclear accumulation, through physical interactions with PIFs and COP1, respectively. Both phyA and phyB, the two best characterized phytochromes, regulate plant photomorphogenesis predominantly under far-red light and red light, respectively. It has been demonstrated that SPA1 (SUPPRESSOR OF PHYTOCHROME A 1) associates with COP1 to promote COP1 activity and suppress photomorphogenesis. Here, we report that the mechanism underlying phyB-promoted photomorphogenesis in red light involves direct physical and functional interactions between red-light-activated phyB and SPA1. We found that SPA1 acts genetically downstream of PHYB to repress photomorphogenesis in red light. Protein interaction studies in both yeast and Arabidopsis demonstrated that the photoactivated phyB represses the association of SPA1 with COP1, which is mediated, at least in part, through red-light-dependent interaction of phyB with SPA1. Moreover, we show that phyA physically interacts with SPA1 in a Pfr-form-dependent manner, and that SPA1 acts downstream of PHYA to regulate photomorphogenesis in far-red light. This study provides a genetic and biochemical model of how photoactivated phyB represses the activity of COP1-SPA1 complex through direct interaction with SPA1 to promote photomorphogenesis in red light.
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Affiliation(s)
- Xue-Dan Lu
- Key Laboratory of Urban Agriculture (South) Ministry of Agriculture and School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
| | - Chuan-Miao Zhou
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), Institute of Plant Physiology and Ecology (SIPPE), Shanghai Institutes for Biological Sciences (SIBS), Shanghai 200032, China
| | - Peng-Bo Xu
- School of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai 200240, China
| | - Qian Luo
- Key Laboratory of Urban Agriculture (South) Ministry of Agriculture and School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China
| | - Hong-Li Lian
- Key Laboratory of Urban Agriculture (South) Ministry of Agriculture and School of Agriculture and Biology, Shanghai Jiaotong University, Shanghai 200240, China.
| | - Hong-Quan Yang
- School of Life Sciences and Biotechnology, Shanghai Jiaotong University, Shanghai 200240, China.
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16
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Ádám É, Kircher S, Liu P, Mérai Z, González-Schain N, Hörner M, Viczián A, Monte E, Sharrock RA, Schäfer E, Nagy F. Comparative functional analysis of full-length and N-terminal fragments of phytochrome C, D and E in red light-induced signaling. THE NEW PHYTOLOGIST 2013; 200:86-96. [PMID: 23772959 DOI: 10.1111/nph.12364] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 05/12/2013] [Indexed: 06/02/2023]
Abstract
Phytochromes (phy) C, D and E are involved in the regulation of red/far-red light-induced photomorphogenesis of Arabidopsis thaliana, but only limited data are available on the mode of action and biological function of these lesser studied phytochrome species. We fused N-terminal fragments or full-length PHYC, D and E to YELLOW FLUORESCENT PROTEIN (YFP), and analyzed the function, stability and intracellular distribution of these fusion proteins in planta. The activity of the constitutively nuclear-localized homodimers of N-terminal fragments was comparable with that of full-length PHYC, D, E-YFP, and resulted in the regulation of various red light-induced photomorphogenic responses in the studied genetic backgrounds. PHYE-YFP was active in the absence of phyB and phyD, and PHYE-YFP controlled responses, as well as accumulation, of the fusion protein in the nuclei, was saturated at low fluence rates of red light and did not require functional FAR-RED ELONGATED HYPOCOTYL1 (FHY-1) and FHY-1-like proteins. Our data suggest that PHYC-YFP, PHYD-YFP and PHYE-YFP fusion proteins, as well as their truncated N-terminal derivatives, are biologically active in the modulation of red light-regulated photomorphogenesis. We propose that PHYE-YFP can function as a homodimer and that low-fluence red light-induced translocation of phyE and phyA into the nuclei is mediated by different molecular mechanisms.
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Affiliation(s)
- Éva Ádám
- Institute of Plant Biology, Biological Research Centre, Temesvári krt.62., H-6726, Szeged, Hungary
| | - Stefan Kircher
- Institute of Botany, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany
| | - Peng Liu
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, 59717, USA
| | - Zsuzsanna Mérai
- Institute of Botany, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany
| | - Nahuel González-Schain
- Departament de Genètica Molecular, Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus Univ. Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Maximilian Hörner
- BIOSS Center for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, D-79104, Freiburg, Germany
| | - András Viczián
- Institute of Plant Biology, Biological Research Centre, Temesvári krt.62., H-6726, Szeged, Hungary
| | - Elena Monte
- Departament de Genètica Molecular, Center for Research in Agricultural Genomics (CRAG) CSIC-IRTA-UAB-UB, Campus Univ. Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Robert A Sharrock
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, MT, 59717, USA
| | - Eberhard Schäfer
- Institute of Botany, University of Freiburg, Schänzlestrasse 1, D-79104, Freiburg, Germany
- BIOSS Center for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, D-79104, Freiburg, Germany
| | - Ferenc Nagy
- Institute of Plant Biology, Biological Research Centre, Temesvári krt.62., H-6726, Szeged, Hungary
- Institute of Molecular Plant Science, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3JH, UK
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17
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Briggs WR, Lin CT. Photomorphogenesis--from one photoreceptor to 14: 40 years of progress. MOLECULAR PLANT 2012; 5:531-2. [PMID: 22610604 DOI: 10.1093/mp/sss059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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