Reconstituting Arabidopsis CRY2 Signaling Pathway in Mammalian Cells Reveals Regulation of Transcription by Direct Binding of CRY2 to DNA

• DOI: 10.1016/j.celrep.2018.06.069
• Publication Date: 2018-07-17T14:45:20Z
• Authors: Liang Yang; Weiliang Mo; Xiaolan Yu; Nan Yao; Zeng Zhou; Xiaolu Fan; Li Zhang; Mingxin Piao; Shiming Li; Dehong Yang; Chentao Lin; Zecheng Zuo
• Keywords: Transcriptional Activation; Light Signal Transduction; Light; Transcription, Genetic; QH301-705.5; 1.1 Normal biological development and functioning; Medical Physiology; Arabidopsis; 03 medical and health sciences; Genetic; Underpinning research; Genetics; Humans; DNA binding; Biology (General); Phosphorylation; transcriptional activity; 0303 health sciences; phosphorylation; Arabidopsis Proteins; blue light specificity; DNA; Biological Sciences; Cryptochromes; Biological sciences; HEK293 Cells; Biochemistry and Cell Biology; Generic health relevance; cryptochrome; Protein Multimerization; Transcription; Protein Binding; Signal Transduction

In response to blue light, cryptochromes photoexcite and interact with signal partners to transduce signal almost synchronously in plants. The detailed mechanism of CRY-mediated light signaling remains unclear: the photobiochemical reactions of cryptochrome are transient and synchronous, thus making the monitoring and analysis of each step difficult in plant cells. In this study, we reconstituted the Arabidopsis CRY2 signaling pathway in mammalian cells and investigated the biological role of Arabidopsis CRY2 in this heterologous system, eliminating the interferences of other plant proteins. Our results demonstrated that, besides being the light receptor, Arabidopsis CRY2 binds to DNA directly and acts as a transcriptional activator in a blue-light-enhanced manner. Similar to classic transcription factors, we found that the transcriptional activity of CRY2 is regulated by its dimerization and phosphorylation. In addition, CRY2 cooperates with CIB1 to regulate transcription by enhancing the DNA affinity and transcriptional activity of CIB1 under blue light.