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The ESCRT III complex consists of at least 18 proteins and is required for the sorting and concentration of proteins resulting in the entry of these proteins into the invaginating vesicles of the multivesicular body (Babst et al. 2002). The sequential action of ESCRT-0, -I, and -II together with the ordered assembly of ESCRT-III links membrane invagination to cargo sorting. Membrane scission in the neck of the growing vesicle releases mature, cargo-laden vesicles into the lumen (Buchkovich et al. 2013, Adell et al. 2014). 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 (Adell et al. 2014). SNF7 is the most abundant ESCRT-III subunit which forms membrane-sculpting filaments with 30 Å periodicity and a exposed cationic membrane-binding surface (Tang et al. 2015). Its activation requires a prominent conformational rearrangement to expose protein-membrane and protein-protein interfaces. SNF7 filaments then form spirals that may function as spiral springs (Chiaruttini et al. 2015). 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. SNF7 recruits BRO1, which in turn recruits DOA4, which deubiquitinates cargos before their enclosure within MVB vesicles (Amerik et al. 2000, Kim et al. 2005). 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 (Webster et al. 2014).Vsp4 is an ATPase that provides the force generation and membrane scission by ESCRT-III (Schöneberg et al. 2018). The sorting of transmembrane proteins (e.g., cell surface receptors) into the multivesicular body (MVB) pathway to the lysosomal/vacuolar lumen requires the function of the ESCRT protein complexes. The soluble coiled-coil-containing proteins Vps2, Vps20, Vps24, and Snf7 are recruited from the cytoplasm to endosomal membranes where they oligomerize into a protein complex, ESCRT-III. ESCRT-III contains two functionally distinct subcomplexes. The Vps20-Snf7 subcomplex binds to the endosomal membrane, in part via the myristoyl group of Vps20. The Vps2-Vps24 subcomplex binds to the Vps20-Snf7 complex and thereby serves to recruit additional cofactors to this site of protein sorting. Evidence for a role for ESCRT-III in sorting and/or concentration of MVB cargoes has been forthcoming (Babst et al. 2002). ESCRT-dependent protein sorting is required for the viability of yeast clathrin-mediated endocytosis mutants (Hoban et al. 2020). The ubiquitin hydrolase, Doa4, directly binds Snf7 to inhibit recruitment of ESCRT-III remodeling factors in S. cerevisiae (Buysse et al. 2020). Bro1 binds the Vps20 subunit of ESCRT-III and promotes ESCRT-III regulation by Doa4 (926 aas, P32571) (Buysse et al. 2022).


Fungi, Ascomycota
ESCRT III of Saccharomyces cerevisiae
Core constituents:
SNF7, DID1, VPS32; 240 aas; P39929
VPS2, DID4, CHM2, GRD7, REN1, VPL2; 232 aas; P36108
VPS24, DID3; 224 aas; P36095
VPS20, ASI1, CHM6, VPT20; 221 aas; Q04272
VPS4 ATPase, CSC1, DID6,END13, GRD13, VPL4; 437 aas; P52917 Plus 20 auxiliary constituents.

The plant ESCRT pathway (ESCRT I, II, III), 25 components included (Ibl 2019). 

Viridiplantae, Streptophyta
ESCRT pathway proteins in Arabidopsis thaliana
Q9LHG8, ELC, ELCH, VAS23A, 398 aas
Q9SKI2, VPS2.1, CHMP2-1, SLP, 225 aas
Q9FF81, VPS36, 440 aas
Q8LE58, VBB46.1, CHMP1A, 203 aas
Q9FY89,  VPB20.2, CHMP6-2, 216 aas
Q9SSM4, VPB46.2, CHMP1B. 203 aas
Q9SZE4, VPS32.2, CHMP4-2, SNF7.1, SNF7B, 219 aas
Q0WTY4, VPS2.2, CHMP2-2, 222 aas
Q9FFB3, VPS24-1, CHMP3-1, 229 aas
O82197, VPS32.1, CHMP4-1, 213 aas
Q9FFY0, VPS23B, ELCL, ELCHL, 368 aas
Q8GXN6, VPS20.1, CHMP6.1, 219 aas
Q9SCP9, VPS37-1, 217 aas
Q9ZNT0, VPS4, SKD1, 435 aas
Q9ASS9, FREE1, FYVE1, 601 aas
F4HXZ1, BRO1, ALIX, SPHR1, 846 aas
Q9SZ15, LIPS, VTA1, 421 aas
Q3EBL9, VPS37-2, 218 aas
Q941D5, VPS2.3, CHMP2-3, 210 aas
Q8VZC9, VPS25, 179 aas
Q9LXH5, VPS24-2, CHMP3-2, 200 aas
Q5M759, VPS22-1, 250 aas
Q65421, VPS28-1, 209 aas
Q9LPN5, VPS60-1, 235 aas
Q9S9T7, VPS28-2, 210 aa

The ESCRT cell division complex consisting of CdvA, CdvB and CdvC (and maybe CdvB1,B2,B3). The majority of Crenarchaeota utilize the cell division system (Cdv) to divide. This system is encoded by three highly conserved genes, cdvA, cdvB and cdvC that are organized in an operon. The CdvA, CdvB and CdvC proteins polymerize between segregating nucleoids and persist throughout cell division, forming a successively smaller structure during constriction (Lindås et al. 2008). CdvA is a membrane interacting protein that recruits ESCRT-III homologs to the membrane (Samson et al. 2011).CdvC is homologous to the AAA-type ATPase Vps4, involved in multivesicular body biogenesis in eukaryotes. CdvA is a unique archaeal protein that interacts with the membrane, while CdvB is homologous to the eukaryal Vps24 and forms helical filaments. Most Crenarcheota contain additional CdvB paralogs. In Sulfolobus acidocaldarius these are termed CdvB1-3. Yang and Driessen 2014 used a gene inactivation approach to determine the impact of these additional cdvB genes on cell division. Independent deletion mutants of these genes were analyzed for growth and protein localization. One of the deletion strains (ΔcdvB3) showed a severe growth defect on plates and delayed growth on liquid medium. It yielded the formation of enlarged cells and a defect in DNA segregation. Since these defects are accompanied by an aberrant localization of CdvA and CdvB, it was concluded that CdvB3 fulfills an important accessory role in cell division.

Archaeal ESCRT cell division complex
CdvA, 238 aas and 0 - 1 TMSs, Q4J923
CdvB, 261 aas and 0 - 3 TMSs, Q4J924
CdvC, 374 aas and 0 TMSs, F2Z6D2 (ATPase)
CdvB1, 214 aas and 0 - 1 TMSs, Q4JBG6
CdvB2, 219 aas and 0 - 1 TMSs, Q4J8Y4
CdvB3, 169 aas and 0 - 2 TMSs, Q4J8G7

Charged multivesicular body protein 4b, Chmp4b of 224 aas. Core component of the endosomal sorting required for transport complex III (ESCRT-III) which is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. The MVB pathway appears to require the sequential function of ESCRT-O, -I,-II and -III complexes (Katoh et al. 2003, Hanson et al. 2008). ESCRT-III proteins mostly dissociate from the invaginating membrane before the ILV is released. The ESCRT machinery also functions in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis (Guizetti et al. 2011). Together with SPAST, the ESCRT-III complex promotes nuclear envelope sealing and mitotic spindle disassembly during late anaphase. Plays a role in the endosomal sorting pathway. ESCRT-III proteins are believed to mediate the necessary vesicle extrusion and/or membrane fission activities, possibly in conjunction with the AAA ATPase VPS4. When overexpressed, membrane-assembled circular arrays of CHMP4B filaments can promote or stabilize negative curvature and outward budding. CHMP4A/B/C are required for the exosomal release of SDCBP, CD63 and syndecan. Chmp4b forms complexes with gap junction proteins during lens fiber cell differentiation(Zhou et al. 2023).

Metazoa, Chordata
Chmp4b of Mus musculus