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MT000928

UniProt Annotations

Entry Information

Gene Name	charged multivesicular body protein 2B
Protein Entry	CHM2B_HUMAN
UniProt ID	Q9UQN3
Species	Human

Comments

Comment type	Description
Alternative Products	Event=Alternative splicing; Named isoforms=2; Name=1; IsoId=Q9UQN3-1; Sequence=Displayed; Name=2; IsoId=Q9UQN3-2; Sequence=VSP_045142;
Disease	Amyotrophic lateral sclerosis 17 (ALS17) [MIM:614696]: An adult-onset progressive neurodegenerative disorder with predominantly lower motor neuron involvement, manifest as muscle weakness and wasting of the upper and lower limbs, bulbar signs, and respiratory insufficiency. {ECO:0000269\|PubMed:16807408, ECO:0000269\|PubMed:20352044}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Disease	Frontotemporal dementia, chromosome 3-linked (FTD3) [MIM:600795]: Characterized by an onset of dementia in the late 50's initially characterized by behavioral and personality changes including apathy, restlessness, disinhibition and hyperorality, progressing to stereotyped behaviors, non-fluent aphasia, mutism and dystonia, with a marked lack of insight. The brains of individuals with FTD3 have no distinctive neuropathological features. They show global cortical and central atrophy, but no beta-amyloid deposits. {ECO:0000269\|PubMed:16041373}. Note=The disease is caused by mutations affecting the gene represented in this entry.
Domain	The acidic C-terminus and the basic N-termminus are thought to render the protein in a closed, soluble and inactive conformation through an autoinhibitory intramolecular interaction. The open and active conformation, which enables membrane binding and oligomerization, is achieved by interaction with other cellular binding partners, probably including other ESCRT components (By similarity). {ECO:0000250}.
Function	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.
Similarity	Belongs to the SNF7 family. {ECO:0000305}.
Subcellular Location	Cytoplasm, cytosol {ECO:0000269\|PubMed:16041373}. Late endosome membrane {ECO:0000305\|PubMed:16041373}; Peripheral membrane protein {ECO:0000305\|PubMed:16041373}.
Subunit	Probable core 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 sequentally. Interacts with CHMP2A. Interacts with VPS4A. Interacts with VPS4B; the interaction is direct. {ECO:0000269\|PubMed:14519844, ECO:0000269\|PubMed:17928862}.
Tissue Specificity	Widely expressed. Expressed in brain, heart, skeletal muscle, spleen, kidney, liver, small intestine, pancreas, lung, placenta and leukocytes. In brain, it is expressed in cerebellum, cerebral cortex, medulla, spinal chord, occipital lobe, frontal lobe, temporal lobe and putamen. {ECO:0000269\|PubMed:16041373}.