Ubiquitin- specific protease UBP14 stabilizes HY5 by deubiquitination to promote photomorphogenesis in Arabidopsis thaliana

• 成果类型: Article
• 署名作者: Fang, Ke; Yao, Xiuhong; Tian, Yu'ang; He, Yang; Lin, Yingru; Lei, Wei; Peng, Sihan; Pan, Guohui; Shi, Haoyu; Zhang, Dawei; Lin, Honghui
• 署名单位: Sichuan University; Yibin University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-15134
• DOI: 10.1073/pnas.2404883121
• 发表日期: 2024-08-13
• 关键词: b-box protein; transcription factors; light control; salt tolerance; cop1; interacts; expression; hypocotyl; receptor; FAMILY

摘要

Transcription factor ELONGATED HYPOCOTYL5 (HY5) is the central hub for seedling photomorphogenesis. E3 ubiquitin (Ub) ligase CONSTITUTIVE PHOTO MORPHOGENIC 1 (COP1) inhibits HY5 protein accumulation through ubiquitination. However, the process of HY5 deubiquitination, which antagonizes E3 ligase- mediated ubiq uitination to maintain HY5 homeostasis has never been studied. Here, we identified that Arabidopsis thaliana deubiquitinating enzyme, Ub- SPECIFIC PROTEASE 14 (UBP14) physically interacts with HY5 and enhances its protein stability by deubiquitination. The da3-1 mutant lacking UBP14 function exhibited a long hypocotyl phenotype, and UBP14 deficiency led to the failure of rapid accumulation of HY5 during dark to light. In addition, UBP14 preferred to stabilize nonphosphorylated form of HY5 which is more readily bound to downstream target genes. HY5 promoted the expression and protein accumulation of UBP14 for positive feedback to facilitate photomorphogenesis. Our findings thus established a mechanism by which UBP14 stabilizes HY5 protein by deu biquitination to promote photomorphogenesis in A. thaliana. Significance For the initial growth of seedlings, the transcription factor ELONGATED HYPOCOTYL5 (HY5) plays a critical role by initiating a series of light responses. Here, we demonstrated that besides transcription activity of HY5, the HY5 protein level, which is stringently regulated by deubiquitinating enzymes, is also vital for photomorphogenesis. We identified a ubiquitin- specific protease, Ub- SPECIFIC PROTEASE 14 (UBP14), which positively promotes plant photomorphogenesis in response to light. UBP14 directly interacts with HY5 and protects it from degradation by 26S proteasomes. Besides, HY5 promotes the expression and protein accumulation of UBP14 for positive feedback. The dynamic regulatory mechanism for UBP14 and HY5 provides an insight into the roles of posttranslational modifications of HY5 during photomorphogenesis in Arabidopsis thaliana.