Charged multivesicular body protein 4b (Chmp4b)

Probable core part of the endosomal sorting required for transport complex III (ESCRT-III) that is involved in multivesicular bodies (MVBs) formation and sorting of endosomal cargo proteins into MVBs. MVBs contain intraluminal vesicles (ILVs) which are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes allowing degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids.

The MVB pathway seems 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.