J Integr Plant Biol ›› 2022, Vol. 64 ›› Issue (9): 1724-1738.DOI: 10.1111/jipb.13331

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  • 收稿日期:2022-05-28 接受日期:2022-07-26 出版日期:2022-09-01 发布日期:2022-09-16

Blue light-induced phosphorylation of Arabidopsis cryptochrome 1 is essential for its photosensitivity

Lin Gao1†, Qing Liu2†*, Ming Zhong3†, Nannan Zeng1, Weixian Deng4, Yaxing Li1, Dong Wang1, Siyuan Liu1 and Qin Wang3*   

  1. 1 College of Life Sciences, Basic Forestry and Proteomics Research Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
    2 School of Life Sciences, State Key Laboratory for Conservation and Utilization of Subtropical Agro‐Bioresources, South China Agricultural University, Guangzhou 510642, China
    3 Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, College of Agriculture, Fujian Agriculture and Forestry University, Fuzhou 350002, China
    4 Department of Biological Chemistry, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA

    †These authors contributed equally to this work.
    *Correspondences: Qing Liu (liuqing2021@scau.edu.cn); Qin Wang (qinwangCRY@163.com; Dr. Wang is fully responsible for the distribution of the materials associated with this article)
  • Received:2022-05-28 Accepted:2022-07-26 Online:2022-09-01 Published:2022-09-16

Abstract:

Plants possess two cryptochrome photoreceptors, cryptochrome 1 (CRY1) and cryptochrome 2 (CRY2), that mediate overlapping and distinct physiological responses. Both CRY1 and CRY2 undergo blue light-induced phosphorylation, but the molecular details of CRY1 phosphorylation remain unclear. Here we identify 19 in vivo phosphorylation sites in CRY1 using mass spectrometry and systematically analyze the physiological and photobiochemical activities of CRY1 variants with phosphosite substitutions. We demonstrate that nonphosphorylatable CRY1 variants have impaired phosphorylation, degradation, and physiological functions, whereas phosphomimetic variants mimic the physiological functions of phosphorylated CRY1 to constitutively inhibit hypocotyl elongation. We further demonstrate that phosphomimetic CRY1 variants exhibit enhanced interaction with the E3 ubiquitin ligase COP1 (CONSTITUTIVELY PHOTOMORPHOGENIC 1). This finding is consistent with the hypothesis that phosphorylation of CRY1 is required for COP1-dependent signaling and regulation of CRY1. We also determine that PHOTOREGULATORY PROTEIN KINASEs (PPKs) phosphorylate CRY1 in a blue light-dependent manner and that this phosphorylation is critical for CRY1 signaling and regulation. These results indicate that, similar to CRY2, blue light-dependent phosphorylation of CRY1 determines its photosensitivity.

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