InnateDB: Systems Biology of the Innate Immune Response

Homo sapiens Protein: CHMP4B

Summary

InnateDB Protein

IDBP-67446.7

Last Modified

2014-10-13 [Report errors or provide feedback]

Gene Symbol

CHMP4B

Protein Name

charged multivesicular body protein 4B

Synonyms

Species

Homo sapiens

Ensembl Protein

ENSP00000217402

InnateDB Gene

IDBG-67444 (CHMP4B)

Protein Structure

UniProt Annotation

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. When overexpressed, membrane-assembled circular arrays of CHMP4B 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. {ECO:0000269PubMed:12860994, ECO:0000269PubMed:14505569, ECO:0000269PubMed:14505570, ECO:0000269PubMed:14519844, ECO:0000269PubMed:18209100}.

Subcellular Localization

Cytoplasm, cytosol. Late endosome membrane {ECO:0000305}; Peripheral membrane protein {ECO:0000305}.

Disease Associations

Cataract 31, multiple types (CTRCT31) [MIM:605387]: An opacification of the crystalline lens of the eye that frequently results in visual impairment or blindness. Opacities vary in morphology, are often confined to a portion of the lens, and may be static or progressive. In general, the more posteriorly located and dense an opacity, the greater the impact on visual function. CTRCT31 includes posterior polar, progressive posterior subcapsular, nuclear, and anterior subcapsular cataracts. {ECO:0000269PubMed:17701905}. Note=The disease is caused by mutations affecting the gene represented in this entry.

Tissue Specificity

Widely expressed. Expressed at higher level in heart and skeletal muscle. Also expressed in brain, colon, thymus, spleen, kidney, liver, small intestine, placenta, lung and peripheral blood lymphocytes. {ECO:0000269PubMed:14678797}.

Comments

Interactions

Number of Interactions

This gene and/or its encoded proteins are associated with 33 experimentally validated interaction(s) in this database.
They are also associated with 1 interaction(s) predicted by orthology.

Experimentally validated
Total	33 [view]
Protein-Protein	33 [view]
Protein-DNA	0
Protein-RNA	0
DNA-DNA	0
RNA-RNA	0
DNA-RNA	0

Predicted by orthology
Total	1 [view]

Gene Ontology

Molecular Function

Accession	GO Term
GO:0005515	protein binding
GO:0042802	identical protein binding
GO:0042803	protein homodimerization activity

Biological Process

GO:0006620	posttranslational protein targeting to membrane
GO:0007034	vacuolar transport
GO:0016032	viral process
GO:0016197	endosomal transport
GO:0019058	viral life cycle
GO:0050792	regulation of viral process
GO:0051260	protein homooligomerization
GO:0061024	membrane organization
GO:1901215	negative regulation of neuron death
GO:1902188	positive regulation of viral release from host cell
GO:1902902	negative regulation of autophagic vacuole assembly

Cellular Component

GO:0000815	ESCRT III complex
GO:0005634	nucleus
GO:0005737	cytoplasm
GO:0005829	cytosol
GO:0009898	cytoplasmic side of plasma membrane
GO:0030496	midbody
GO:0031902	late endosome membrane
GO:0070062	extracellular vesicular exosome