Key Lab of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
College of Advanced Agricultural Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
Nat Commun. 2024 Jul 16;15(1):5987. doi: 10.1038/s41467-024-50290-4.
Ethylene regulates plant growth, development, and stress adaptation. However, the early signaling events following ethylene perception, particularly in the regulation of ethylene receptor/CTRs (CONSTITUTIVE TRIPLE RESPONSE) complex, remains less understood. Here, utilizing the rapid phospho-shift of rice OsCTR2 in response to ethylene as a sensitive readout for signal activation, we revealed that MHZ3, previously identified as a stabilizer of ETHYLENE INSENSITIVE 2 (OsEIN2), is crucial for maintaining OsCTR2 phosphorylation. Genetically, both functional MHZ3 and ethylene receptors prove essential for OsCTR2 phosphorylation. MHZ3 physically interacts with both subfamily I and II ethylene receptors, e.g., OsERS2 and OsETR2 respectively, stabilizing their association with OsCTR2 and thereby maintaining OsCTR2 activity. Ethylene treatment disrupts the interactions within the protein complex MHZ3/receptors/OsCTR2, reducing OsCTR2 phosphorylation and initiating downstream signaling. Our study unveils the dual role of MHZ3 in fine-tuning ethylene signaling activation, providing insights into the initial stages of the ethylene signaling cascade.
乙烯调节植物的生长、发育和应激适应。然而，乙烯感知后的早期信号事件，特别是在乙烯受体/CTRs（组成性三重反应）复合物的调节方面，仍了解较少。在这里，我们利用水稻 OsCTR2 对乙烯的快速磷酸化转换作为信号激活的敏感读数，揭示了先前被鉴定为 ETHYLENE INSENSITIVE 2（OsEIN2）稳定剂的 MHZ3 对于维持 OsCTR2 磷酸化至关重要。从遗传学角度来看，功能性 MHZ3 和乙烯受体都证明对于 OsCTR2 磷酸化是必需的。MHZ3 与亚家族 I 和 II 乙烯受体（例如，OsERS2 和 OsETR2）分别相互作用，稳定它们与 OsCTR2 的结合，从而维持 OsCTR2 的活性。乙烯处理破坏了 MHZ3/受体/OsCTR2 蛋白复合物内的相互作用，降低了 OsCTR2 的磷酸化并启动下游信号转导。我们的研究揭示了 MHZ3 在精细调节乙烯信号激活中的双重作用，为乙烯信号级联的初始阶段提供了新的见解。
