CHMP1A

Probable peripherally associated component of theendosomal sorting required for transport complex III (ESCRT-III)which is involved in multivesicular bodies (MVBs) formation andsorting of endosomal cargo proteins into MVBs. MVBs containintraluminal vesicles (ILVs) that are generated by invagination andscission from the limiting membrane of the endosome and mostly aredelivered to lysosomes enabling degradation of membrane proteins,such as stimulated growth factor receptors, lysosomal enzymes andlipids. The MVB pathway appears to require the sequential functionof ESCRT-O, -I,-II and -III complexes. ESCRT-III proteins mostlydissociate from the invaginating membrane before the ILV isreleased. The ESCRT machinery also functions in topologicallyequivalent membrane fission events, such as the terminal stages ofcytokinesis and the budding of enveloped viruses (HIV-1 and otherlentiviruses). ESCRT-III proteins are believed to mediate thenecessary vesicle extrusion and/or membrane fission activities,possibly in conjunction with the AAA ATPase VPS4. Involved incytokinesis. Involved in recruiting VPS4A and/or VPS4B to themidbody of dividing cells. May also be involved in chromosomecondensation. Targets the Polycomb group (PcG) protein BMI1/PCGF4to regions of condensed chromatin. May play a role in stable cellcycle progression and in PcG gene silencing.