title: Organization of protein complexes under photomorphogenic UV-B in Arabidopsis.
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.
authors.affiliation: Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology; National Laboratory of Protein Engineering and Plant Genetic Engineering; College of Life Sciences; Peking University; Beijing, PR China.
authors.forename: Xi
authors.initials: X
authors.lastname: Huang
authors.affiliation: Peking-Yale Joint Center for Plant Molecular Genetics and Agro-Biotechnology; National Laboratory of Protein Engineering and Plant Genetic Engineering; College of Life Sciences; Peking University; Beijing, PR China.
authors.forename: Xing Wang
authors.initials: XW
authors.lastname: Deng
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D008954:Models, Biological; D009024:Morphogenesis / Q000528:radiation effects*; D046912:Multiprotein Complexes / Q000378:metabolism*; D015398:Signal Transduction / Q000528:radiation effects; D014466:Ultraviolet Rays
chemical_list: D029681:Arabidopsis Proteins; D046912:Multiprotein Complexes
keywords: UV-B; light signaling; protein complex