Vacuolar Protein Sorting 4 Homolog B (VPS4B) Human Recombinant Protein

The protein encoded by this gene is a member of the AAA protein family (ATPases associated with diverse cellular activities), and is the homolog of the yeast Vps4 protein. In humans, two paralogs of the yeast protein have been identified. The former share a high degree of aa sequence similarity with each other, and also with yeast Vps4 and mouse Skd1 proteins. Mouse Skd1 (suppressor of K+ transport defect 1) has been shown to be a yeast Vps4 ortholog. Functional studies indicate that both human paralogs associate with the endosomal compartments, and are involved in intracellular protein trafficking, similar to Vps4 protein in yeast. The gene encoding this paralog has been mapped to chromosome 18; the gene for the other resides on chromosome 16. [provided by RefSeq, Jul 2008]

VPS4B: 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. 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). Belongs to the AAA ATPase family.

Protein type: Vesicle; EC 3.6.4.6

Chromosomal Location of Human Ortholog: 18q21.33

Cellular Component: spindle pole; centrosome; late endosome membrane; lysosome; late endosome; early endosome; vacuolar membrane; cytoplasm; endosome membrane; nucleus; cytosol; endosome

Molecular Function: protein C-terminus binding; protein binding; ATPase activity; ATPase activity, coupled; microtubule-severing ATPase activity; ATP binding

Biological Process: ubiquitin-dependent protein catabolic process via the multivesicular body pathway; viral reproduction; cell separation during cytokinesis; endosome organization and biogenesis; regulation of viral reproduction; intracellular cholesterol transport; viral infectious cycle; protein depolymerization; response to lipid; endosome transport; mitotic metaphase plate congression; endosome to lysosome transport via multivesicular body sorting pathway; cytoplasmic microtubule organization and biogenesis; protein transport; nuclear organization and biogenesis; potassium ion transport; vacuole organization and biogenesis