FEATURES

FAMILY

DESCRIPTION

Also known as VPS4B_HUMAN, VPS4B, SKD1, VPS42. Involved in late steps of the endosomal multivesicular bodies (MVB) pathway. Recognizes membrane-associated ESCRT-III assemblies and catalyzes their disassembly, possibly in combination with membrane fission. Redistributes the ESCRT-III components to the cytoplasm for further rounds of MVB sorting. MVBs contain intraluminal vesicles (ILVs) that are generated by invagination and scission from the limiting membrane of the endosome and mostly are delivered to lysosomes enabling degradation of membrane proteins, such as stimulated growth factor receptors, lysosomal enzymes and lipids. VPS4A/B are required for the exosomal release of SDCBP, CD63 and syndecan (PubMed:22660413)., (Microbial infection) In conjunction with the ESCRT machinery also appears to function in topologically equivalent membrane fission events, such as the terminal stages of cytokinesis and enveloped virus budding (HIV-1 and other lentiviruses). Proposed to be monomeric or homodimeric in nucleotide-free form and to oligomerize upon binding to ATP to form two stacked hexameric or heptameric rings with a central pore through which ESCRT-III substrates are translocated in an ATP-dependent manner. In vitro, associates on the inside of a helical tubular structure formed by a CHMP2A-CHMP3 polymer. Interacts with CHMP1A, CHMP1B, CHMP2A, CHMP4B and CHMP6. Interacts with VPS4A; the interaction suggests a heteromeric assembly with VPS4A. Interacts with VTA1.

EXTERNAL LINKS

VPS4B

Vacuolar protein sorting-associated protein 4B

VPS4B

Molecular Synopsis