Scientific article
Open access

Mechanisms of UV-B light-induced photoreceptor UVR8 nuclear localization dynamics

Published inNew phytologist, vol. 236, no. 5, p. 1824-1837
Publication date2022-12
First online date2022-09-21

Light regulates the subcellular localization of plant photoreceptors, a key step in light signaling. Ultraviolet-B radiation (UV-B) induces the plant photoreceptor UV RESISTANCE LOCUS 8 (UVR8) nuclear accumulation, where it regulates photomorphogenesis. However, the molecular mechanism for the UV-B-regulated UVR8 nuclear localization dynamics is unknown. With fluorescence recovery after photobleaching (FRAP), cell fractionation followed by immunoblotting and co-immunoprecipitation (Co-IP) assays we tested the function of UVR8-interacting proteins including CONSTITUTIVELY PHOTOMORPHOGENIC 1 (COP1), REPRESSOR OF UV-B PHOTOMORPHOGENESIS 1 (RUP1) and RUP2 in the regulation of UVR8 nuclear dynamics in Arabidopsis thaliana. We showed that UV-B-induced rapid UVR8 nuclear translocation is independent of COP1, which previously was shown to be required for UV-B-induced UVR8 nuclear accumulation. Instead, we provide evidence that the UV-B-induced UVR8 homodimer-to-monomer photo-switch and the concurrent size reduction of UVR8 enables its monomer nuclear translocation, most likely via free diffusion. Nuclear COP1 interacts with UV-B-activated UVR8 monomer, thereby promoting UVR8 nuclear retention. Conversely, RUP1and RUP2, whose expressions are induced by UV-B, inhibit UVR8 nuclear retention via attenuating the UVR8-COP1 interaction, allowing UVR8 to exit the nucleus. Collectively, our data suggest that UV-B-induced monomerization of UVR8 promotes its nuclear translocation via free diffusion. In the nucleus, COP1 binding promotes UVR8 monomer nuclear retention, which is counterbalanced by the major negative regulators RUP1 and RUP2.

  • Arabidopsis
  • Nuclear import
  • Photomorphogenesis
  • Photoreceptor
  • Tomato
  • Arabidopsis Proteins / metabolism
  • Chromosomal Proteins, Non-Histone / metabolism
  • Signal Transduction
  • Arabidopsis / metabolism
  • Photoreceptors, Plant / metabolism
  • Ultraviolet Rays
  • Ubiquitin-Protein Ligases / metabolism
  • Gene Expression Regulation, Plant
Research group
  • National Natural Science Foundation of China - [31870261]
  • National Natural Science Foundation of China - [32070261]
  • National Natural Science Foundation of China - [32170246]
  • the Medicine and Engineering interdisciplinary Research Fund of SJTU - [YG2021ZD07]
  • China Postdoctoral Science Foundation - [2021M692072]
  • National Key Research and Development Program of China - [2018YFD1000800]
  • Natural Science Foundation of Shanghai - [22ZR1431300]
  • Swiss National Science Foundation - Perception and signalling of UV-B radiation in plants [31003A_175774]
Citation (ISO format)
FANG, Fang et al. Mechanisms of UV-B light-induced photoreceptor UVR8 nuclear localization dynamics. In: New phytologist, 2022, vol. 236, n° 5, p. 1824–1837. doi: 10.1111/nph.18468
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Article (Published version)
Secondary files (1)
ISSN of the journal0028-646X

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