Acts a component of the ESCRT-III complex required for the sorting and concentration of proteins resulting in the entry of these proteins into the invaginating vesicles of the multivesicular body (MVB) (PubMed:11559748, PubMed:12194857). The sequential action of ESCRT-0, -I, and -II together with the ordered assembly of ESCRT-III links membrane invagination to cargo sorting (PubMed:12194857). Membrane scission in the neck of the growing vesicle releases mature, cargo-laden ILVs into the lumen (PubMed:24139821, PubMed:24711499). ESCRT-III is critical for late steps in MVB sorting, such as membrane invagination and final cargo sorting and recruitment of late-acting components of the sorting machinery (PubMed:24139821, PubMed:24711499). SNF7 is the most abundant ESCRT-III subunit which forms membrane-sculpting filaments with 30 Angstrom periodicity and a exposed cationic membrane-binding surface (PubMed:26670543). Its activation requires a prominent conformational rearrangement to expose protein-membrane and protein-protein interfaces (PubMed:26670543). SNF7 filaments then form spirals that could function as spiral springs (PubMed:26522593). The elastic expansion of compressed SNF7 spirals generates an area difference between the two sides of the membrane and thus curvature which could be the origin of membrane deformation leading eventually to fission (PubMed:26522593). SNF7 recruits BRO1, which in turn recruits DOA4, which deubiquitinates cargos before their enclosure within MVB vesicles (PubMed:11029042, PubMed:15935782). ESCRT-III is also recruited to the nuclear envelope (NE) by integral INM proteins to surveil and clear defective nuclear pore complex (NPC) assembly intermediates to ensure the fidelity of NPC assembly (PubMed:25303532). Core component of the ESCRT-III complex (endosomal sorting required for transport complex III) (PubMed:12194857, PubMed:18854142). ESCRT-III appears to be sequentially assembled as a flat lattice on the endosome membrane and forms a transient 450 kDa complex that contains DID4, oligomerized SNF7, VPS20 and VPS24 (PubMed:18854142). SNF7 polymerizes into spirals at the surface of lipid bilayers (PubMed:26522593). SNF7 polymerization is nucleated by association of SNF7 with VPS20; the process is terminated through association of VPS24, possibly by capping the SNF7 filament (PubMed:24058170, PubMed:24711499). Interacts with VTA1; the interaction requires DID2 (PubMed:16601096, PubMed:24058170). Interacts with BRO1 (PubMed:15086794, PubMed:15935782, PubMed:24058170). Interacts with DOA4 (PubMed:26427873). Interacts with HEH1 and HEH2 (PubMed:25303532). Interacts with RIM20 and YGR122W (PubMed:24058170). The N-terminus (residues 1 to 11) forms an amphipathic helix which is required for the association to membrane. Exhibits defects in the sorting and processing of native vacuolar proteins (PubMed:3062374). Present with 3270 molecules/cell in log phase SD medium. Belongs to the SNF7 family. Was originally thought to be a nuclear protein and mutations were shown to prevent full derepression of the SUC2 (invertase) gene. On releasing tension - Issue 180 of June 2016