Biomolecular condensation of ERC1 recruits ATG8 and NBR1 to drive autophagosome formation for plant heat tolerance
Abstract
Macroautophagy (hereafter autophagy) is essential for cells to respond to nutrient deficiency by delivering cytosolic contents to vacuoles for degradation via the formation of a multilayer organelle named an autophagosome. A set of autophagy-related (ATG) regulators are recruited to the phagophore assembly site for phagophore initiation, including its expansion and closure, and subsequent delivery into the vacuole. However, it remains elusive how the phagophore assembly is regulated under different stress conditions. Here, we described an uncharacterized Arabidopsis ( Arabidopsis thaliana ) ERC (ELKS/Rab6-interacting/CAST) protein family as an interacting partner of ATG8. ERC1 proteins translocate to the phagophore membrane and develop into ring-like autophagosomes upon autophagic induction. Notably, we found that ERC1 proteins possess the ability to assemble into substantial droplets together with ATG8e proteins prior to ATG8 conjugation to the membrane. Through multiscale characterization, we demonstrated that the ERC1 membraneless droplet represents a distinct type of plant condensate. Additionally, ERC1 directly binds to NBR1 to promote NBR1 degradation. ERC1 dysfunction suppresses the turnover of ubiquitinated substrates and compromises plant tolerance to heat stress. Our study suggests a model for autophagic degradation in response to heat stress by the action of ERC1-mediated biomolecular condensation in Arabidopsis .
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (17)
Ka Kit Chung
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Kai Ching Law
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Ziwei Zhao
Juncai Ma
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Xiao-Tong Zhan
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Cheuk Him Chiang
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Kwan Ho Leung
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Ruben Shrestha
Division of Biosphere Sciences and Engineering, Carnegie Science
Yixin Wu
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Chaorui Li
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Ka Ming Lee
School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Lei Feng
Xibao Li
Guangdong Provincial Key Laboratory of Biotechnology for Plant Development, School of Life Sciences, Ministry of Education Key Laboratory & Guangdong Provincial Key Laboratory of Laser Life Science, College of Biophotonics, South China Normal University
Kam Bo Wong
School of Life Sciences, Centre for Protein Science and Crystallography, State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong
Shou-Ling Xu
Division of Biosphere Sciences and Engineering, Carnegie Science
Caiji Gao
Xiaohong Zhuang
School of Life Sciences, Centre for Plant Vacuole Biology and Biotechnology, Centre for Cell & Developmental Biology and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong