Vps20

Vps20, short for Vacuolar Protein Sorting 20, is a conserved eukaryotic protein that serves as a subunit of the ESCRT-III complex. In yeast and other organisms, it participates in the late stages of endosomal sorting by promoting membrane remodeling that leads to the formation of intralumenal vesicles within multivesicular bodies (MVBs). Vps20 is typically associated with endosomal membranes and acts as a nucleator for ESCRT-III assembly by recruiting other subunits, notably Snf7/Vps32, to the site of vesicle formation. Once ESCRT-III filaments have formed, additional subunits such as Vps24 and Vps2 contribute to polymer remodeling and cargo sequestration. The ESCRT-III apparatus is eventually disassembled by the AAA-ATPase Vps4, allowing recycling of components.

In mammals, the closest ortholog of Vps20 is CHMP6 (charged multivesicular body protein 6), which performs a similar role in ESCRT-III assembly and function. CHMP6 interacts with other ESCRT-III components, including the CHMP4 family, and with VPS4 ATPases, to drive endosomal sorting, cytokinesis, and membrane repair processes.

Functionally, VPS20/CHMP6 is essential for proper trafficking of ubiquitinated cargo to the lysosome/vacuole in yeast and higher eukaryotes. Disruption of Vps20/Vps20-like function impairs MVB formation and can affect receptor downregulation and membrane protein turnover.