CHMP4A
Description
The CHMP4A (charged multivesicular body protein 4A) is a protein-coding gene located on chromosome 14.
Charged multivesicular body protein 4a is a protein that in humans is encoded by the CHMP4A gene.
CHMP4A is a core component of the ESCRT-III complex, essential for the formation of multivesicular bodies (MVBs). MVBs are involved in sorting and delivering endosomal cargo proteins, including growth factor receptors, lysosomal enzymes, and lipids, to lysosomes for degradation. The process involves invagination and scission of the endosome membrane to form intraluminal vesicles (ILVs) within MVBs. ESCRT-III proteins, including CHMP4A, work sequentially with other ESCRT complexes (ESCRT-O, -I, and -II) to mediate this process. After ILV formation, ESCRT-III proteins dissociate from the membrane. Beyond MVB formation, the ESCRT machinery plays a role in other membrane fission events, such as cytokinesis and the budding of enveloped viruses like HIV-1. CHMP4A contributes to the necessary vesicle extrusion and membrane fission activities, potentially in conjunction with the VPS4 ATPase. Overexpression of CHMP4A leads to the assembly of filaments that can promote or stabilize negative membrane curvature and outward budding. CHMP4A's interaction with PDCD6IP is linked to HIV-1 p6- and p9-dependent virus release. Additionally, CHMP4A, along with CHMP4B and CHMP4C, is required for the exosomal release of proteins like SDCBP, CD63, and syndecan.
CHMP4A is also known as C14orf123, CHMP4, CHMP4B, HSPC134, SHAX2, SNF7, SNF7-1, VPS32-1, VPS32A, hSnf7-1.
