CUL3 BPM E3 ubiquitin ligases regulate MYC2, MYC3, and MYC4 stability and JA responses

Jasmonates (JAs) are essential phytohormones that regulate many developmental and defensive responses in plants. The transcription factors MYC2, MYC3 and MYC4 play an essential role in signaling by activating the gene program mediated by JAs. However, the continuous activation of the response to JAs by MYC factors inhibits growth which is potentially lethal to the plant. Consequently, the activity of the MYC proteins must be strictly regulated. In this study, the researchers highlighted the role of the proteins BTB / POZ AND MATH DOMAIN (BPM) as a regulator in the signaling pathway of JAs. Thus, by a genetic and biochemical approach, they have shown that the MYC proteins are the direct targets of BPMs which act as substrate adapters for ubiquitin ligase type CRL3. This selective degradation reaction of the MYC proteins is a key step in the mechanism for resetting the JA signal. This work, the result of an international collaboration, was published in PNAS on March 2, 2020.







Figure legend: Volcano plot depicting the GFP-BPM6 enriched proteins. Green dots represent enriched BPM proteins, whereas red dots represent enriched proteins of interest, among which MYC proteins.