SUMMARY PARAGRAPH for VPS20
Most proteins targeted for degradation in the multivesicular body (MVB) pathway are monoubiquitinated, then passed through the series of highly-conserved multisubunit complexes known as ESCRT (Endosomal Sorting Complex Required for Transport). ESCRT I, II, and III are sequentially mobilized to endosomal membranes, where they direct protein sorting and MVB biogenesis, and play a crucial role in retrovirus budding (7).
The formation of ESCRT III - composed of subcomplexes Snf7p-Vps20p and Did4p-Vps24p - is transient and appears to be dependent on ESCRT II (8, 4). Snf7p-Vps20p effects the membrane association of ESCRT III, with Snf7p being required for localization of the Bro1p vacuolar protein sorting factor to endosomes (9, 10). Vps20p is myristoylated by Nmt1p, which is required for its localization to the endosomal membrane and for formation of ESCRT III (11, 4). Vps20p is also important for interaction between ESCRT III, ESCRT II, and ESCRT I, and may be involved in regulating the Vps4p AAA-type ATPase, which is necessary for the dissociation of ESCRT III (8, 5, 6, 7). Did4p-Vps24p is required for endosomal localization of Vps4p and the Doa4p ubiquitin hydrolase (4, 12).
Last updated: 2006-03-08