ESCRTKomplex

ESCRTKomplex, commonly referred to as the ESCRT complex, is a collection of conserved protein assemblies that mediate membrane remodeling and scission events in eukaryotic cells. Its best characterized role is in the endosomal pathway, where it coordinates the sorting of ubiquitinated membrane proteins into intralumenal vesicles within multivesicular bodies, directing them to lysosomal degradation.

The ESCRT machinery comprises four core assemblies—ESCRT-0, ESCRT-I, ESCRT-II and ESCRT-III—together with the Vps4 ATPase and accessory factors. In humans, ESCRT-0 contains HRS and STAM1/2; ESCRT-I includes TSG101, VPS28 and VPS37 family members with MVB12; ESCRT-II consists of VPS22, VPS25 and VPS36; ESCRT-III is a heterogeneous group of CHMP proteins that assemble into filaments.

Cargo recognition by ESCRT-0/I-II concentrates cargo at the membrane, while ESCRT-III drives membrane constriction and scission from the cytoplasmic side. The Vps4 ATPase disassembles ESCRT-III after membrane fission to recycle components, aided by cofactors such as VTA1 and ALIX in specific contexts. The sequential action of these complexes ensures selective cargo sorting and membrane remodeling required for vesicle formation.

Beyond endosomal trafficking, ESCRT components participate in other cellular processes that require membrane scission away from the cytoplasm, including abscission during cytokinesis, budding of some enveloped viruses, plasma membrane repair, and certain autophagic steps.

The ESCRT system is evolutionarily conserved across eukaryotes; archaea possess ESCRT-III and Vps4 homologs. Dysfunction in ESCRT pathways is linked to trafficking defects and disease, and the machinery is studied as a potential target in antiviral and cancer research.