Molecular basis for blue light-dependent phosphorylation of Arabidopsis cryptochrome 2

• Published in: Nature communications Vol. 8; no. 1; p. 15234
• Main Authors: Liu, Qing, Wang, Qin, Deng, Weixian, Wang, Xu, Piao, Mingxin, Cai, Dawei, Li, Yaxing, Barshop, William D, Yu, Xiaolan, Zhou, Tingting, Liu, Bin, Oka, Yoshito, Wohlschlegel, James, Zuo, Zecheng, Lin, Chentao
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 11.05.2017; Nature Portfolio
• Subjects: Adenosine; Amino Acid Sequence; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis - radiation effects; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Circadian rhythm; Cryptochromes - genetics; Cryptochromes - metabolism; Gene Expression Regulation, Plant; Isoenzymes - genetics; Isoenzymes - metabolism; Kinases; Light; Peptides; Phosphorylation; Phosphorylation - radiation effects; Phosphoserine - metabolism; Phosphotransferases (Alcohol Group Acceptor) - genetics; Phosphotransferases (Alcohol Group Acceptor) - metabolism; Photoreceptors; Physiology; Phytochrome - genetics; Phytochrome - metabolism; Protein Processing, Post-Translational; Protein-Serine-Threonine Kinases - genetics; Protein-Serine-Threonine Kinases - metabolism; Proteins; Signal transduction; Los Angeles California; California; United States > US; China
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/ncomms15234

Plant cryptochromes undergo blue light-dependent phosphorylation to regulate their activity and abundance, but the protein kinases that phosphorylate plant cryptochromes have remained unclear. Here we show that photoexcited Arabidopsis cryptochrome 2 (CRY2) is phosphorylated in vivo on as many as 24 different residues, including 7 major phosphoserines. We demonstrate that four closely related Photoregulatory Protein Kinases (previously referred to as MUT9-like kinases) interact with and phosphorylate photoexcited CRY2. Analyses of the ppk123 and ppk124 triple mutants and amiR artificial microRNA-expressing lines demonstrate that PPKs catalyse blue light-dependent CRY2 phosphorylation to both activate and destabilize the photoreceptor. Phenotypic analyses of these mutant lines indicate that PPKs may have additional substrates, including those involved in the phytochrome signal transduction pathway. These results reveal a mechanism underlying the co-action of cryptochromes and phytochromes to coordinate plant growth and development in response to different wavelengths of solar radiation in nature.