Structural elucidation of how ARF small GTPases induce membrane tubulation for vesicle fission

• 成果类型: Article
• 署名作者: Pang, Xiaoyun; Zhang, Yan; Park, Kunyou; Liao, Zhenyu; Li, Jian; Xu, Jiashu; Hong, Minh-Triet; Yin, Guoliang; Zhang, Tongming; Wang, Yaoyu; Egelman, Edward H.; Fan, Jun; Hsu, Victor W.; Park, Seung-Yeol; Sun, Fei
• 署名单位: Chinese Academy of Sciences; Institute of Biophysics, CAS; Pohang University of Science & Technology (POSTECH); Harvard University; Harvard Medical School; Harvard University Medical Affiliates; Brigham & Women's Hospital; Harvard University; Harvard Medical School; City University of Hong Kong; City University of Hong Kong; Chinese Academy of Sciences; University of Chinese Academy of Sciences, CAS; University of Virginia; Chinese Academy of Sciences; Institute of Biophysics, CAS; Chinese Academy of Sciences; Guangzhou Institute of Biomedicine & Health, CAS
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-11057
• DOI: 10.1073/pnas.2417820122
• 发表日期: 2025-03-25
• 关键词: adp-ribosylation factor; coated vesicles; gtp-binding; proteins; complex; RECRUITMENT; coatomer; copii; CURVATURE; mechanism

摘要

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 & Aring; 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.