Organization of protein complexes under photomorphogenic UV-B in Arabidopsis

Plant Signal Behav. 2013 Nov;8(11):e27206. doi: 10.4161/psb.27206. Epub 2013 Dec 4.

Abstract

Low-fluence and long-wavelength UV-B (UV-B) light promotes photomorphogenic development in Arabidopsis. CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1) is a positive regulator in this pathway while it is a negative regulator of the traditional photomorphogenesis triggered by far-red and visible light. We have recently reported the mechanism by which the switch of COP1 function is accomplished in distinct light contexts. In response to photomorphogenic UV-B, the photoactivated UV RESISTANCE LOCUS 8 (UVR8) associates with the COP1- SUPRESSOR OF PHYA (SPA) core complexes, resulting in the physical and functional disassociation of COP1-SPA from the CULLIN4-DAMAGED DNA BINDING PROTEIN 1 (CUL4-DDB1) E3 scaffold. These UV-B dependent UVR8-COP1-SPA complexes promote the stability and activity of ELONGATED HYPOCOTYL 5 (HY5), and eventually cause COP1 to switch from repressing to promoting photomorphogenesis. In addition, it is possible that CUL4-DDB1 might simultaneously recruit alternative DDB1 BINDING WD40 (DWD) proteins to repress this UV-B-specific signaling. Further investigation is required, however, to verify this hypothesis. Overall, the coordinated organization of various protein complexes facilitates an efficient and balanced UV-B signaling.

Keywords: UV-B; light signaling; protein complex.

MeSH terms

  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis / radiation effects*
  • Arabidopsis Proteins / metabolism*
  • Models, Biological
  • Morphogenesis / radiation effects*
  • Multiprotein Complexes / metabolism*
  • Signal Transduction / radiation effects
  • Ultraviolet Rays*

Substances

  • Arabidopsis Proteins
  • Multiprotein Complexes