CHMP4B

Chr 20q11.22

charged multivesicular body protein 4B

Aliases:: dJ553F4.4, Shax1, SNF7-2, VPS32B
MANE:: ENST00000217402.3

OMIM: 610897 ↗NCBI: 128866 ↗Ensembl ↗

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Predicted protein structure

AlphaFold predicted structure

CHMP4B · Q9H444

v62025-08-01

Predicted Aligned Error matrix for CHMP4B — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

78.9/ 100

Confident

224 residues

Confidence breakdown

Very high(≥ 90)43%
Confident(70–90)29%
Low(50–70)13%
Very low(< 50)15%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

Bilateral congenital or childhood onset cataracts
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Structural eye disease
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted

Disease associations (Open Targets)

Posterior polar cataract
0.66
early-onset non-syndromic cataract
0.56
neurodegenerative disease
0.54
viral infectious disease
0.46
HIV infectious disease
0.46
diabetes mellitus
0.41
type 2 diabetes mellitus
0.40
COVID-19
0.37
early-onset posterior polar cataract
0.37
severe acute respiratory syndrome
0.37

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Charged multivesicular body protein 4b

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 (PubMed:12860994, PubMed:18209100). The ESCRT machinery also functions in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis (PubMed:21310966). Together with SPAST, the ESCRT-III complex promotes nuclear envelope sealing and mitotic spindle disassembly during late anaphase (PubMed:26040712). Plays a role in the endosomal sorting pathway. 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. CHMP4A/B/C are required for the exosomal release of SDCBP, CD63 and syndecan (PubMed:22660413). Majority of the protein exists in a folded closed conformation (PubMed:33349255)