title: Negative membrane curvature catalyzes nucleation of endosomal sorting complex required for transport (ESCRT)-III assembly.
abstract: The endosomal sorting complexes required for transport (ESCRT) machinery functions in HIV-1 budding, cytokinesis, multivesicular body biogenesis, and other pathways, in the course of which it interacts with concave membrane necks and bud rims. To test the role of membrane shape in regulating ESCRT assembly, we nanofabricated templates for invaginated supported lipid bilayers. The assembly of the core ESCRT-III subunit CHMP4B/Snf7 is preferentially nucleated in the resulting 100-nm-deep membrane concavities. ESCRT-II and CHMP6 accelerate CHMP4B assembly by increasing the concentration of nucleation seeds. Superresolution imaging was used to visualize CHMP4B/Snf7 concentration in a negatively curved annulus at the rim of the invagination. Although Snf7 assemblies nucleate slowly on flat membranes, outward growth onto the flat membrane is efficiently nucleated at invaginations. The nucleation behavior provides a biophysical explanation for the timing of ESCRT-III recruitment and membrane scission in HIV-1 budding.
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720;
authors.forename: Il-Hyung
authors.initials: IH
authors.lastname: Lee
authors.affiliation: California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720; Department of Chemistry, University of California, Berkeley, CA 94720;
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kai
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720;
authors.forename: Lars-Anders
authors.initials: LA
authors.lastname: Carlson
authors.affiliation: California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720; Department of Chemistry, University of California, Berkeley, CA 94720; Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; Mechanobiology Institute, National University of Singapore, Singapore 117411.
authors.forename: Jay T
authors.initials: JT
authors.lastname: Groves
authors.affiliation: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720; California Institute for Quantitative Biosciences, University of California, Berkeley, CA 94720; Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720; jimhurley@berkeley.edu.
authors.forename: James H
authors.initials: JH
authors.lastname: Hurley
mesh_terms: D000465:Algorithms; D002462:Cell Membrane / Q000378:metabolism* / Q000821:virology; D056827:Endosomal Sorting Complexes Required for Transport / Q000378:metabolism*; D011992:Endosomes / Q000378:metabolism*; D036681:Fluorescence Recovery After Photobleaching; D006678:HIV / Q000502:physiology; D006801:Humans; D008051:Lipid Bilayers / Q000378:metabolism*; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D021381:Protein Transport; D014779:Virus Replication
chemical_list: C478397:CHMP4B protein, human; C481528:CHMP6 protein, human; D056827:Endosomal Sorting Complexes Required for Transport; D008051:Lipid Bilayers
keywords: HIV-1; membrane bending; nanofabrication; superresolution imaging