Biomolecular condensates of ATG18 reshape ER forautophagy in plants by Yang Shao & Xunzheng Li & Benhui Shi & Songyang Wang & Zisheng Luo & Yanqun Xu & Baolei Li & Shuqing Feng & Li Liang & Huanquan Zheng & Jiaqi Sun instant download

Biomolecular condensates of ATG18 reshape ER forautophagy in plants by Yang Shao & Xunzheng Li & Benhui Shi & Songyang Wang & Zisheng Luo & Yanqun Xu & Baolei Li & Shuqing Feng & Li Liang & Huanquan Zheng & Jiaqi Sun instant download

SUMMARYAutophagosomes originate from and maintain association with the endoplasmic reticulum (ER) during theirformation, yet how these processes are molecularly coordinated in plants remains poorly understood. Here,we demonstrate that Arabidopsis autophagy-related protein 18a (ATG18a), a key organizer of early autophagosome formation, undergoes phase separation to form biomolecular condensates on the ER membrane,which progress from highly mobile droplets to stable ring-like structures, while the ER is reshaped. Wediscovered that ATG18a condensates work together with ROOT HAIR DEFECTIVE3 (RHD3), an ER membrane-shaping protein, with RABC1 serving as a molecular linker between them. Importantly, RABC1 facilitates both RHD3 assembly necessary for the formation of ring-like ER structures and its interaction withATG18a condensates. These findings reveal a mechanism whereby biomolecular condensates work togetherwith membrane-shaping proteins to reshape specialized membrane domains through wetting interactions,providing an insight into autophagosome formation in plant stress responses.