Reciprocal antagonistic regulation of E3 ligases controls ACC synthase stability and responses to stress
Han Yong Lee, Hye Lin Park, Chanung Park, Yi‐Chun Chen, Gyeong Mee Yoon
Abstract
Significance Protein homeostasis is critical for the proper growth and development of organisms. In ethylene biosynthesis, the protein abundance of ACC synthases (ACS), the rate-limiting enzymes in ethylene biosynthesis, is critical to control ethylene production and is regulated in part through crosstalk with other phytohormones. However, the underlying mechanism including regulatory components that integrate the crosstalk is poorly understood. This study identified a mechanism that employs the reciprocal degradation of two E3 ligase components to control the stability of ACS in a brassinosteroid and phosphoprotein-binding protein-dependent manner. The disruption of the reciprocal degradation between the E3 ligases compromises the survival of plants under carbon starvation. These findings have implications for understanding ethylene biosynthesis regulation, protein homeostasis, and its associated stress response.