6TZ4 image
Entry Detail
PDB ID:
6TZ4
EMDB ID:
EMD-20588
Keywords:
LIPID BINDING PROTEIN
Title:
CryoEM reconstruction of membrane-bound ESCRT-III filament composed of CHMP1B+IST1 (right-handed)
Biological Source:
Source Organism:
Homo sapiens
Host Organism:
Escherichia coli
PDB Version:
Deposition Date:
2019-08-10
Release Date:
2020-04-08
Method Details:
Experimental Method:
ELECTRON MICROSCOPY
Resolution:
3.20 Å
Aggregation State:
HELICAL ARRAY
Reconstruction Method:
HELICAL
6TZ4 validation report
Macromolecular Entities
Protein Blast
Polymer Type:polypeptide(L)
Description:Charged multivesicular body protein 1b
Mutations:K37E
Chain IDs:A (auth: JB), C (auth: A), E (auth: C), G (auth: E), I (auth: G), K (auth: I), M (auth: K), O (auth: M), Q (auth: O), S (auth: Q), U (auth: S), W (auth: V), Y (auth: X), AA (auth: Z), CA (auth: BA), EA (auth: DA), GA (auth: FA), IA (auth: HA), KA (auth: JA), MA (auth: LA), OA (auth: NA), QA (auth: PA), SA (auth: RA), UA (auth: TA), WA (auth: VA), YA (auth: XA), AB (auth: ZA), CB (auth: BB), EB (auth: DB), GB (auth: FB), IB (auth: HB), KB (auth: LB), MB (auth: NB), OB (auth: PB), QB (auth: RB), SB (auth: 02)
Chain Length:199
Number of Molecules:36
Biological Source:Homo sapiens
UniProt ID:Q7LBR1 Pfam ID:PF03357
Protein Blast
Polymer Type:polypeptide(L)
Description:IST1 homolog
Chain IDs:B (auth: MB), D (auth: B), F (auth: D), H (auth: F), J (auth: H), L (auth: J), N (auth: L), P (auth: N), R (auth: P), T (auth: R), V (auth: T), X (auth: W), Z (auth: Y), BA (auth: AA), DA (auth: CA), FA (auth: EA), HA (auth: GA), JA (auth: IA), LA (auth: KA), NA (auth: MA), PA (auth: OA), RA (auth: QA), TA (auth: SA), VA (auth: UA), XA (auth: WA), ZA (auth: YA), BB (auth: AB), DB (auth: CB), FB (auth: EB), HB (auth: GB), JB (auth: IB), LB (auth: KB), NB (auth: OB), PB (auth: QB), RB (auth: SB), TB (auth: 01)
Chain Length:189
Number of Molecules:36
Biological Source:Homo sapiens
UniProt ID:P53990 Pfam ID:PF03398
Ligand Molecules
NA
Primary Citation
Membrane constriction and thinning by sequential ESCRT-III polymerization.
Nat.Struct.Mol.Biol. 27 392 399 (2020)
PMID: 32251413 DOI: 10.1038/s41594-020-0404-x

Abstact

The endosomal sorting complexes required for transport (ESCRTs) mediate diverse membrane remodeling events. These typically require ESCRT-III proteins to stabilize negatively curved membranes; however, recent work has indicated that certain ESCRT-IIIs also participate in positive-curvature membrane-shaping reactions. ESCRT-IIIs polymerize into membrane-binding filaments, but the structural basis for negative versus positive membrane remodeling by these proteins remains poorly understood. To learn how certain ESCRT-IIIs shape positively curved membranes, we determined structures of human membrane-bound CHMP1B-only, membrane-bound CHMP1B + IST1, and IST1-only filaments by cryo-EM. Our structures show how CHMP1B first polymerizes into a single-stranded helical filament, shaping membranes into moderate-curvature tubules. Subsequently, IST1 assembles a second strand on CHMP1B, further constricting the membrane tube and reducing its diameter nearly to the fission point. Each step of constriction thins the underlying bilayer, lowering the barrier to membrane fission. Our structures reveal how a two-component, sequential polymerization mechanism drives membrane tubulation, constriction and bilayer thinning.

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Primary Citation of related structures
6TZ4