Plant Rho GTPase signaling promotes autophagy

• 作者: Youshun Lin Yonglun Zeng Ying Zhu Jinbo Shen Hao Ye Liwen Jiang
• 来源期刊: 分子植物（英文版）
• 年，卷（期）: 2021,（6）
• 所属期刊栏目: Research Articles
• 页码范围: 905-920
• 页数: 16页
• 语种: 英文

摘要

The roles of Rho family guanosine triphosphatases(GTPases)of plants(ROPs)in modulating plant growth and development have been well characterized.However,little is known about the roles of ROP signaling pathways in regulating plant autophagy and autophagosome formation.In this study,we identify a unique ROP signaling mechanism,which mediates developmental to autophagic transition under stress condi-tions in the model plant Arabidopsis.Loss-of-function mutants ofROP8 showed stress-induced hypersen-sitive phenotypes and compromised autophagic flux.Similar to other ROPs in the ROP/RAC family,ROP8 exhibits both plasma membrane and cytosolic punctate localization patterns.Upon autophagic induction,active ROP8 puncta colocalize with autophagosomal markers and are degraded inside the vacuole.In hu-man cells,RaIB,an RAS subfamily GTPase,engages its effector Exo84 for autophagosome assembly.How-ever,a RaIB counterpart is missing in the plant lineage.Intriguingly,we discovered that plant ROP8 pro-motes autophagy via its downstream effector Sec5.Live-cell super-resolution imaging showed that ROP8 and Sec5 reside on phagophores for autophagosome formation.Taken together,our findings high-light a previously unappreciated role of an ROP8-Sec5 signaling axis in autophagy promotion,providing new insights into how plants utilize versatile ROP signaling networks to coordinate developmental and au-tophagic responses depending on environmental changes.