CHMP1B

CHMP1B belongs to the chromatin-modifying protein/charged multivesicular body protein (CHMP) family. These proteins are components of ESCRT-III (endosomal sorting complex required for transport III), a complex involved in degradation of surface receptor proteins and formation of endocytic multivesicular bodies (MVBs). Some CHMPs have both nuclear and cytoplasmic/vesicular distributions, and one such CHMP, CHMP1A (MIM 164010), is required for both MVB formation and regulation of cell cycle progression (Tsang et al., 2006 [PubMed 16730941]).[supplied by OMIM, Mar 2008]

Full Name

Charged Multivesicular Body Protein 1B

Function

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 and the budding of enveloped viruses (HIV-1 and other lentiviruses). 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. Involved in HIV-1 p6- and p9-dependent virus release.

Biological Process

Cell division Source: UniProtKB
Endosome transport via multivesicular body sorting pathway Source: GO_Central
ESCRT III complex disassembly Source: ParkinsonsUK-UCL
Establishment of protein localization Source: UniProtKB
Late endosome to vacuole transport Source: GO_Central
Midbody abscission Source: UniProtKB
Mitotic metaphase plate congression Source: UniProtKB
Multivesicular body assembly Source: ParkinsonsUK-UCL
Nucleus organization Source: UniProtKB
Protein transport Source: GO_Central
Regulation of centrosome duplication Source: UniProtKB
Regulation of mitotic spindle assembly Source: UniProtKB
Viral budding via host ESCRT complex Source: UniProtKB

Cellular Location

Endosome; Late endosome membrane; Cytosol. Localizes to the midbody of dividing cells, colocalizing with CEP55 and CHMP5. Localized at the periphery of the Fleming body.