7XRD

Cryo-EM structure of Arf6 helical polymer assembled on lipid membrane

Summary for 7XRD

• Entry DOI: 10.2210/pdb7xrd/pdb
• EMDB information: 33414
• Descriptor: ADP-ribosylation factor 6, MAGNESIUM ION, GUANOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: small gtpase, helical polymer, membrane tubulation, lipid binding protein
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 4
• Total formula weight: 86390.42

Authors

Pang, X.Y.,Zhang, Y.,Sun, F. (deposition date: 2022-05-10, release date: 2023-11-15, Last modification date: 2025-05-28)

Primary citation

Pang, X.,Zhang, Y.,Park, K.,Liao, Z.,Li, J.,Xu, J.,Hong, M.T.,Yin, G.,Zhang, T.,Wang, Y.,Egelman, E.H.,Fan, J.,Hsu, V.W.,Park, S.Y.,Sun, F.
Structural elucidation of how ARF small GTPases induce membrane tubulation for vesicle fission.
Proc.Natl.Acad.Sci.USA, 122:e2417820122-e2417820122, 2025

PubMed 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.

PubMed: 40117306
DOI: 10.1073/pnas.2417820122

Experimental method

ELECTRON MICROSCOPY (3.9 Å)