Chromatin Modifying Protein 4a (CHMP4A) Human Recombinant Protein

CHMP4A 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]

CHMP4A: Probable 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. 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. When overexpressed, membrane-assembled circular arrays of CHMP4A filaments can promote or stabilize negative curvature and outward budding. Via its interaction with PDCD6IP involved in HIV-1 p6- and p9-dependent virus release. Belongs to the SNF7 family.

Chromosomal Location of Human Ortholog: 14q12

Cellular Component: internal side of plasma membrane; cytoplasmic vesicle membrane; membrane coat; late endosome membrane; cytoplasm; plasma membrane; midbody; nucleus; cytosol; endosome

Molecular Function: identical protein binding; protein binding; protein homodimerization activity; lipid binding; ATPase binding

Biological Process: protein polymerization; cell separation during cytokinesis; viral reproduction; vacuolar transport; membrane invagination; viral infectious cycle; posttranslational protein targeting to membrane; endosome transport; mitotic metaphase plate congression; nuclear organization and biogenesis; protein homooligomerization; membrane budding