4RQW

Crystal structure of Myc3 N-terminal JAZ-binding domain [44-238] from Arabidopsis

Summary for 4RQW

• Entry DOI: 10.2210/pdb4rqw/pdb
• Related: 4RRU
• Descriptor: Transcription factor MYC3, CALCIUM ION (3 entities in total)
• Functional Keywords: helix-sheet-helix fold, transcription factor, jaz repressors, nuclear, transcription regulator
• Biological source: Arabidopsis thaliana (mouse-ear cress,thale-cress)
• Cellular location: Nucleus : Q9FIP9
• Total number of polymer chains: 2
• Total formula weight: 43536.77

Authors

Ke, J.,Zhang, F.,Zhou, X.E.,Brunzelle, J.,Zhou, M.,Xu, H.E.,Melcher, K.,He, S.Y. (deposition date: 2014-11-05, release date: 2015-08-12, Last modification date: 2024-10-30)

Primary citation

Zhang, F.,Yao, J.,Ke, J.,Zhang, L.,Lam, V.Q.,Xin, X.F.,Zhou, X.E.,Chen, J.,Brunzelle, J.,Griffin, P.R.,Zhou, M.,Xu, H.E.,Melcher, K.,He, S.Y.
Structural basis of JAZ repression of MYC transcription factors in jasmonate signalling.
Nature, 525:269-273, 2015

PubMed Abstract: The plant hormone jasmonate plays crucial roles in regulating plant responses to herbivorous insects and microbial pathogens and is an important regulator of plant growth and development. Key mediators of jasmonate signalling include MYC transcription factors, which are repressed by jasmonate ZIM-domain (JAZ) transcriptional repressors in the resting state. In the presence of active jasmonate, JAZ proteins function as jasmonate co-receptors by forming a hormone-dependent complex with COI1, the F-box subunit of an SCF-type ubiquitin E3 ligase. The hormone-dependent formation of the COI1-JAZ co-receptor complex leads to ubiquitination and proteasome-dependent degradation of JAZ repressors and release of MYC proteins from transcriptional repression. The mechanism by which JAZ proteins repress MYC transcription factors and how JAZ proteins switch between the repressor function in the absence of hormone and the co-receptor function in the presence of hormone remain enigmatic. Here we show that Arabidopsis MYC3 undergoes pronounced conformational changes when bound to the conserved Jas motif of the JAZ9 repressor. The Jas motif, previously shown to bind to hormone as a partly unwound helix, forms a complete α-helix that displaces the amino (N)-terminal helix of MYC3 and becomes an integral part of the MYC N-terminal fold. In this position, the Jas helix competitively inhibits MYC3 interaction with the MED25 subunit of the transcriptional Mediator complex. Our structural and functional studies elucidate a dynamic molecular switch mechanism that governs the repression and activation of a major plant hormone pathway.

PubMed: 26258305
DOI: 10.1038/nature14661

Experimental method

X-RAY DIFFRACTION (2.2 Å)