title: Structural analysis and modeling reveals new mechanisms governing ESCRT-III spiral filament assembly.
abstract: The scission of biological membranes is facilitated by a variety of protein complexes that bind and manipulate lipid bilayers. ESCRT-III (endosomal sorting complex required for transport III) filaments mediate membrane scission during the ostensibly disparate processes of multivesicular endosome biogenesis, cytokinesis, and retroviral budding. However, mechanisms by which ESCRT-III subunits assemble into a polymer remain unknown. Using cryogenic electron microscopy (cryo-EM), we found that the full-length ESCRT-III subunit Vps32/CHMP4B spontaneously forms single-stranded spiral filaments. The resolution afforded by two-dimensional cryo-EM combined with molecular dynamics simulations revealed that individual Vps32/CHMP4B monomers within a filament are flexible and able to accommodate a range of bending angles. In contrast, the interface between monomers is stable and refractory to changes in conformation. We additionally found that the carboxyl terminus of Vps32/CHMP4B plays a key role in restricting the lateral association of filaments. Our findings highlight new mechanisms by which ESCRT-III filaments assemble to generate a unique polymer capable of membrane remodeling in multiple cellular contexts.
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Qing-Tao
authors.initials: QT
authors.lastname: Shen
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Amber L
authors.initials: AL
authors.lastname: Schuh
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Yuqing
authors.initials: Y
authors.lastname: Zheng
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Kyle
authors.initials: K
authors.lastname: Quinney
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Michael
authors.initials: M
authors.lastname: Hanna
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Julie C
authors.initials: JC
authors.lastname: Mitchell
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Marisa S
authors.initials: MS
authors.lastname: Otegui
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Paul
authors.initials: P
authors.lastname: Ahlquist
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Cui
authors.affiliation: Department of Biomolecular Chemistry, School of Medicine and Public Health, Department of Botany, Department of Genetics, Department of Chemistry, Graduate Program in Biophysics, Department of Mathematics, Department of Biochemistry, Institute for Molecular Virology, Howard Hughes Medical Institute, and Morgridge Institute for Research, University of Wisconsin-Madison, Madison, WI 53706 audhya@wisc.edu.
authors.forename: Anjon
authors.initials: A
authors.lastname: Audhya
mesh_terms: D000818:Animals; D017173:Caenorhabditis elegans / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D018360:Crystallography, X-Ray; D056827:Endosomal Sorting Complexes Required for Transport / Q000096:biosynthesis* / Q000648:ultrastructure*; D008854:Microscopy, Electron; D056004:Molecular Dynamics Simulation; D011108:Polymers / Q000378:metabolism; D011487:Protein Conformation; D055503:Protein Multimerization; D021122:Protein Subunits / Q000096:biosynthesis / Q000378:metabolism*
chemical_list: D056827:Endosomal Sorting Complexes Required for Transport; D011108:Polymers; D021122:Protein Subunits