Structural elucidation of how ARF small GTPases induce membrane tubulation for vesicle fission
Abstract
ADP-Ribosylation Factor (ARF) small GTPases have been found to act in vesicle fission through a direct ability to tubulate membrane. We have pursued cryoelectron microscopy (EM) to reveal at 3.9 Å resolution how ARF6 assembles into a protein lattice on tubulated membrane. Molecular dynamics simulation studies confirm and extend the cryo-EM findings. The ARF6 lattice exhibits features that are distinct from those formed by other membrane-bending proteins. We identify protein contacts critical for lattice assembly and how membrane insertion results in constricted tubules. The lattice structure also enables docking by GTPase-activating proteins (GAP) to achieve vesiculation. We have also modeled ARF1 onto the ARF6 lattice, and then pursued vesicle reconstitution by the Coat Protein I (COPI) complex to further confirm that the ARF lattice acts in vesicle fission. By elucidating how an ARF protein tubulates membrane at the structural level, we have advanced the molecular understanding of how this class of transport factors promote the fission stage of vesicle formation.
Article Details
Journal Info
Proceedings of the National Academy of Sciences
National Academy of Sciences
Authors (15)
Xiaoyun Pang
Key Laboratory of Biomacromolecules (Chinese Academy of Sciences), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences
Yan Zhang
Kunyou Park
Department of Life Sciences, Pohang University of Science and Technology
Zhenyu Liao
Department of Materials Science and Engineering, and Center for Advanced Nuclear Safety and Sustainable Development, City University of Hong Kong
Jian Li
Jiashu Xu
Key Laboratory of Biomacromolecules (Chinese Academy of Sciences), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences
Minh-Triet Hong
Department of Life Sciences, Pohang University of Science and Technology
Guoliang Yin
Key Laboratory of Biomacromolecules (Chinese Academy of Sciences), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences
Tongming Zhang
Key Laboratory of Biomacromolecules (Chinese Academy of Sciences), National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences
Yaoyu Wang
Edward H. Egelman
Department of Biochemistry and Molecular Genetics
Jun Fan
Department of Materials Science and Engineering
Victor W. Hsu
Division of Rheumatology, Inflammation and Immunity, Brigham and Women’s Hospital, and Department of Medicine, Harvard Medical School
Seung-Yeol Park
Department of Life Sciences, Pohang University of Science and Technology
Fei Sun