CHMP2B : charged multivesicular body protein 2B
Description
The CHMP2B (charged multivesicular body protein 2B) is a protein-coding gene located on chromosome 3.
The CHMP2B gene provides instructions for making a protein called charged multivesicular body protein 2B. This protein is active in the brain, where it appears to be essential for the survival of nerve cells (neurons). Charged multivesicular body protein 2B forms one part (subunit) of a group of proteins known as the ESCRT-III complex. This complex helps transport other proteins from the cell membrane to the interior of the cell, a process known as endocytosis. In particular, the ESCRT-III complex is involved in the endocytosis of proteins that need to be broken down (degraded) by the cell. The complex helps sort these proteins into structures called multivesicular bodies (MVBs), which deliver them to lysosomes. Lysosomes are compartments within cells that digest and recycle many different types of molecules. Charged multivesicular body protein 2B is regulated by a segment at one end of the protein known as the C-terminal domain. This domain usually keeps the protein turned off (inactive). The inactive protein is unable to interact with other subunits of the ESCRT-III complex, which prevents the complex from forming when it is not needed. The C-terminal domain also plays an important role in disassembling the ESCRT-III complex through its interaction with a protein called vacuolar protein sorting 4 (Vps4).
CHMP2B is a core component of the ESCRT-III complex, which plays a crucial role in the formation of multivesicular bodies (MVBs). MVBs are essential for the sorting and degradation of cellular cargo proteins, including growth factor receptors, lysosomal enzymes, and lipids. The ESCRT-III complex facilitates the invagination and scission of the endosomal membrane, creating intraluminal vesicles (ILVs) within MVBs. These MVBs are then transported to lysosomes, where the cargo proteins are degraded. The ESCRT machinery functions in a sequential manner, involving ESCRT-0, -I, -II, and -III complexes. CHMP2B, as part of the ESCRT-III complex, helps to disassemble the complex after ILV formation. The ESCRT machinery also participates in other membrane fission events, such as cytokinesis and the budding of enveloped viruses.
CHMP2B is also known as ALS17, CHMP2.5, DMT1, FTDALS7, VPS2-2, VPS2B.
Associated Diseases
- Behavioral variant of frontotemporal dementia
- Frontotemporal dementia and/or amytrophic lateral sclerosis 7
- Amyotrophic lateral sclerosis
- Semantic dementia
- Progressive non-fluent aphasia
- CHMP2B-related frontotemporal dementia
