The nuclear envelope is a membrane system which surrounds the nucleoplasm of eukaryotic cells. It is composed of the nuclear lamina, nuclear pore complexes and two nuclear membranes. The space between the two membranes is called the nuclear intermembrane space.
Acts a component of the ESCRT-III complex required for the sorting and concentration of proteins resulting in the entry of these proteins into the invaginating vesicles of the multivesicular body (MVB) (PubMed:11559748, PubMed:12194857). The sequential action of ESCRT-0, -I, and -II together with the ordered assembly of ESCRT-III links membrane invagination to cargo sorting (PubMed:12194857). Membrane scission in the neck of the growing vesicle releases mature, cargo-laden ILVs into the lumen (PubMed:24139821, PubMed:24711499). ESCRT-III is critical for late steps in MVB sorting, such as membrane invagination and final cargo sorting and recruitment of late-acting components of the sorting machinery (PubMed:24139821, PubMed:24711499). SNF7 is the most abundant ESCRT-III subunit which forms membrane- sculpting filaments with 30 Angstrom periodicity and a exposed cationic membrane-binding surface (PubMed:26670543). Its activation requires a prominent conformational rearrangement to expose protein-membrane and protein-protein interfaces (PubMed:26670543). SNF7 filaments then form spirals that could function as spiral springs (PubMed:26522593). The elastic expansion of compressed SNF7 spirals generates an area difference between the two sides of the membrane and thus curvature which could be the origin of membrane deformation leading eventually to fission (PubMed:26522593). SNF7 recruits BRO1, which in turn recruits DOA4, which deubiquitinates cargos before their enclosure within MVB vesicles (PubMed:11029042, PubMed:15935782). ESCRT-III is also recruited to the nuclear envelope (NE) by integral INM proteins to surveil and clear defective nuclear pore complex (NPC) assembly intermediates to ensure the fidelity of NPC assembly (PubMed:25303532). {Experimental EvidencePubMed:11559748, Experimental EvidencePubMed:12194857, Experimental EvidencePubMed:15935782, Experimental EvidencePubMed:24139821, Experimental EvidencePubMed:24711499, Experimental EvidencePubMed:25303532, Experimental EvidencePubMed:26522593, Experimental EvidencePubMed:3062374}.
Vacuolar-sorting protein BRO1 (Amino acid sensor-independent protein 6) (BCK1-like resistance to osmotic shock protein 1) (BRO domain-containing protein 1) (Nitrogen permease inactivating protein 3) (Vacuolar protein-sorting-associated protein 31)
Vacuolar protein-sorting-associated protein 46 (Charged multivesicular body protein 1) (DOA4-independent degradation protein 2) (Fifty two inhibitor 1)
Vacuolar protein sorting-associated protein 20 (Amino acid sensor-independent protein 10) (Charged multivesicular body protein 6) (ESCRT-III complex subunit VPS20) (Vacuolar protein-targeting protein 20)
National and Kapodistrian University of Athens
Department of Biology
Biophysics & Bioinformatics Laboratory