ESCRT-0 recruits ESCRT-I and thereby initiates the MVB pathway. Cargo Sorting ESCRT-I is a heterotetramer consisting of Vps23, Vps28, Vps37, and Mvb12. The UEV domain of Vps23 binds ubiquitinated membrane proteins. Vps28 interacts with the GLUE domain of Vps36 in ESCRT-II. Cargo Sorting ESCRT-II is a heterotetramer formed of Vps36, Vps22, and two Vps25 molecules. The GLUE domain of Vps36 binds PI3P, Vps28, and ubiquitinated membrane proteins. Vps25 interacts with Vps20 of ESCRT-III.