Figure 7. Models of Snf7 activation, polymer assembly and membrane remodeling.

(A) Space-filling CONSURF models with high conservation (purple) and low conservation (cyan). Interacting protomers shown in ribbon (blue). Seven conserved regions with assigned functions labeled. Gray arrows indicate the flexibility of α4. (B) Speculative cartoons illustrating four stages in ESCRT-mediated vesicle budding. (C) Space-filling models and schematic cartoons of Snf7^core in closed and open states with membrane (grey). (D) Space-filling and close-up ribbon models of a 25-mer Snf7 single filament with membrane. (E) Space-filling and close-up ribbon models of a 23-mer Snf7 normal mode analysis filament with membrane (grey). (F) Schematic of a Snf7 homo-polymer in the neck of a nascent ILV with positive and negative membrane curvatures.

DOI: http://dx.doi.org/10.7554/eLife.12548.030

Figure 7—figure supplement 1. Alignment of Snf7^core protein sequences from Saccharomyces cerevisiae (Sc), Homo sapiens (Hs), Mus musculus (Mm), Xenopus laevis (Xl), Drosophila melanogaster (Dm), Caenorhabditis elegans (Ce), Schizosaccharomyces pombe (Sp) and Lokiarchea (Spang et al., 2015).

DOI: http://dx.doi.org/10.7554/eLife.12548.031

Figure 7—figure supplement 2. A ribbon model of a supercomplex of Vps25-Vps20-Snf7.

The first Snf7’s α1 was used for superimposing with the Vps20 α1 (Im et al., 2009) (PDB: 3HTU) for molecular docking.

DOI: http://dx.doi.org/10.7554/eLife.12548.032

Figure 7—figure supplement 3. Architectures of Snf7 protofilaments.

(A) A representative TEM image of recombinant Snf7^R52E (left) and a space-filling model of a 61-mer Snf7^α1-3 straight filament shown in the same scale (right). (B) A representative TEM image of recombinant full-length Snf7^R52E, Vps24 and Vps2 (2:1:1) (left), and space-filling and close-up view of ribbon models of a 97-mer Snf7^α1-3 superhelix generated by normal mode analysis with measured dimensions (right). TEM scale bars, 50nm.

DOI: http://dx.doi.org/10.7554/eLife.12548.033