Arabidopsis ECAP Is a New Adaptor Protein that Connects JAZ Repressors with the TPR2 Co-repressor to Suppress Jasmonate-Responsive Anthocyanin Accumulation

• Published in: Molecular plant 2020-02, Vol.13 (2), p.246-265
• Main Authors: Li, Changjiang, Shi, Lei, Wang, Yanan, Li, Wei, Chen, Binqing, Zhu, Lei, Fu, Ying
• Format: Article
• Language: English
• Subjects: adaptor proteins; Adaptor Proteins, Signal Transducing - chemistry; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Amino Acid Motifs; anthocyanin; Anthocyanins - metabolism; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - genetics; Arabidopsis Proteins - metabolism; Cell Nucleus - metabolism; Co-Repressor Proteins - metabolism; Cyclopentanes - metabolism; ECAP; Gene Expression Regulation, Plant; jasmonate signaling; JAZ proteins; Molecular Chaperones - metabolism; Oxylipins - metabolism; Protein Binding; Protein Interaction Domains and Motifs; Repressor Proteins - chemistry; Repressor Proteins - genetics; Repressor Proteins - metabolism; Signal Transduction; TPL/TPRs; Trans-Activators - metabolism
• ISSN: 1674-2052; 1752-9867
• DOI: 10.1016/j.molp.2019.10.014

Suppression mechanisms mediated by transcriptional repressors commonly exist in diverse phytohormone signaling pathways. In Arabidopsis thaliana, JASMONATE-ZIM DOMAIN (JAZ) proteins are transcriptional repressors that function as negative regulators of diverse JA responses. Novel Interactor of JAZ (NINJA) is an adaptor protein connecting JAZs with the co-repressor, TOPLESS (TPL), to mediate gene repression in JA-dependent root growth inhibition and defense pathways. However, whether NINJA or other adaptor proteins are employed in other JA-responsive biological processes remains to be elucidated. In the present study, we demonstrate that a previously uncharacterized protein, ECAP (EAR motif-Containing Adaptor Protein), directly interacts with JAZ6 and JAZ8 and enhances their transcriptional repression activities. We provide evidence that ECAP is a novel adaptor protein for JAZ6/8 recruitment of the transcriptional co-repressor, TOPLESS-RELATED 2 (TPR2), into a transcriptional repressor complex that represses the WD-repeat/bHLH/MYB complex, an important transcriptional activator in the JA-dependent anthocyanin biosynthesis pathway. Our findings, together with previous reports, reveal that specific adaptor proteins play a critical role in distinct JA responses by pairing different JAZs (which possess overlapping but also specific functions) with the general co-repressors, TPL and TPRs. Suppression mechanisms mediated by transcriptional repressors play an important role in jasmonate signaling. This study reports that ECAP acts as a novel adaptor protein, and connects JAZ6/8 with the co-transcriptional repressor TPR2 to form a transcriptional repression complex, which inhibits the activity of the WD-repeat/bHLH/MYB complex in the jasmonate-induced anthocyanin biosynthesis pathway.