Targeted Degradation of MYC2 through MPK6 Phosphorylation Reveals Mechanisms and Implications for JA Signaling

MYC2 is a key regulator in the Jasmonic acid (JA) signaling pathway, yet the mechanisms governing its stability remain unclear. In this study, we demonstrate that MYC2 is degraded by MPK6 under JA signaling. Through yeast two-hybrid and co-immunoprecipitation assays, and in vitro kinase assay, we show that MPK6 directly interacts with and phosphorylates MYC2. Additionally, MYC2 transcriptional activity is enhanced in the mpk6 mutant. Further, MPK6 phosphorylates MYC2 at threonine 328, leading to its degradation. These findings suggest that MPK6 drives MYC2 degradation by specifically phosphorylating threonine 328 within the JA signaling pathway.