title: The Blue Light-Dependent Polyubiquitination and Degradation of Arabidopsis Cryptochrome2 Requires Multiple E3 Ubiquitin Ligases.
abstract: Cryptochromes are blue light receptors regulated by light-dependent ubiquitination and degradation in both plant and animal lineages. The Arabidopsis genome encodes two cryptochromes, CRY1 and CRY2, of which CRY2 undergoes blue light-dependent ubiquitination and 26S proteasome-dependent degradation. The molecular mechanism regulating blue light-dependent proteolysis of CRY2 is still not fully understood. We found that the F-box proteins ZEITLUPE (ZTL) and Lov Kelch Protein2 (LKP2), which mediate blue light suppression of degradation of the CRY2 signaling partner CIB1, are not required for the blue light-dependent CRY2 degradation. We further showed that the previously reported function of the COP1-SPA1 protein complex in blue light-dependent CRY2 degradation is more likely to be attributable to its cullin 4 (CUL4)-based E3 ubiquitin ligase activity than its activity as the cryptochrome signaling partner. However, the blue light-dependent CRY2 degradation is only partially impaired in the cul4 mutant, the cop1-5 null mutant and the spa1234 quadruple mutant, suggesting a possible involvement of additional E3 ubiquitin ligases in the regulation of CRY2. Consistent with this hypothesis, we demonstrated that the blue light-dependent CRY2 degradation is significantly impaired in the temperature-sensitive cul1 mutant allele (axr6-3), especially under the non-permissive temperature. Based on these and other results presented, we propose that photoexcited CRY2 undergoes Lys48-linked polyubiquitination catalyzed by the CUL4- and CUL1-based E3 ubiquitin ligases.
authors: Laboratory of Soil and Plant Molecular Genetics, College of Plant Science, Jilin University, Changchun 130062, China.|Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA.
authors: Qing
authors: Q
authors: Liu
authors: Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA.
authors: Qin
authors: Q
authors: Wang
authors: Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
authors: Bin
authors: B
authors: Liu
authors: Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
authors: Wei
authors: W
authors: Wang
authors: Basic Forestry and Proteomics Research Center, Haixia Institute of Science and Technology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.|Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA.
authors: Xu
authors: X
authors: Wang
authors: Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA.
authors: Joon
authors: J
authors: Park
authors: Laboratory of Soil and Plant Molecular Genetics, College of Plant Science, Jilin University, Changchun 130062, China.
authors: Zhenming
authors: Z
authors: Yang
authors: Laboratory of Soil and Plant Molecular Genetics, College of Plant Science, Jilin University, Changchun 130062, China bianmingdiucla@163.com xldu@jlu.edu.cn.
authors: Xinglin
authors: X
authors: Du
authors: Laboratory of Soil and Plant Molecular Genetics, College of Plant Science, Jilin University, Changchun 130062, China bianmingdiucla@163.com xldu@jlu.edu.cn.
authors: Mingdi
authors: M
authors: Bian
authors: Laboratory of Soil and Plant Molecular Genetics, College of Plant Science, Jilin University, Changchun 130062, China.|Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA.
authors: Chentao
authors: C
authors: Lin
mesh_terms: D017360:Arabidopsis / Q000378:metabolism* / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism; D056931:Cryptochromes; D008027:Light; D008239:Lysine / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D025821:Polyubiquitin / Q000378:metabolism*; D000072417:Protein Domains; D059748:Proteolysis / Q000528:radiation effects*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D054875:Ubiquitination / Q000528:radiation effects*
chemical_list: D029681:Arabidopsis Proteins; C103618:CRY2 protein, Arabidopsis; D056931:Cryptochromes; D025821:Polyubiquitin; D044767:Ubiquitin-Protein Ligases; D008239:Lysine
keywords: Arabidopsis thaliana; CRY2; Degradation; Ubiquitin E3 ligase