Probable peripherally associated 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. 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. ESCRT-III proteins are believed to mediate the necessary vesicle extrusion and/or membrane fission activities, possibly in conjunction with the AAA ATPase VPS4. Involved in cytokinesis. Involved in recruiting VPS4A and/or VPS4B and SPAST to the midbody of dividing cells (By similarity). Probable peripherally associated component of the endosomal sorting required for transport complex III (ESCRT-III). ESCRT-III components are thought to multimerize to form a flat lattice on the perimeter membrane of the endosome. Several assembly forms of ESCRT-III may exist that interact and act sequentially. Interacts with CHMP1A. Interacts with VTA1; the interaction probably involves the open conformation of CHMP1B. Interacts with CHMP2A. Interacts with VPS4A; the interaction is direct. Interacts with VPS4B; the interaction is direct. Interacts with SPAST (via MIT domain); the interaction is direct. Interacts with IST1. Interacts with MITD1. Interacts with STAMBP (By similarity). Localizes to the midbody of dividing cells, colocalizing with CEP55 and CHMP5. Localized at the periphery of the Fleming body (By similarity). Belongs to the SNF7 family.