Anti-PSMB5/MB1 Antibody Picoband®

Proteasome subunit beta type-5 as known as 20S proteasome subunit beta-5 is a protein that in humans is encoded by the PSMB5 gene. The proteasome is a multicatalytic proteinase complex with a highly ordered ring-shaped 20S core structure. The core structure is composed of 4 rings of 28 non-identical subunits; 2 rings are composed of 7 alpha subunits and 2 rings are composed of 7 beta subunits. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway. An essential function of a modified proteasome, the immunoproteasome, is the processing of class I MHC peptides. This gene encodes a member of the proteasome B-type family, also known as the T1B family, that is a 20S core beta subunit in the proteasome. This catalytic subunit is not present in the immunoproteasome and is replaced by catalytic subunit 3i (proteasome beta 8 subunit) . Multiple transcript variants encoding different isoforms have been found for this gene.

Vacuolar protein sorting-associated protein 4B; Cell migration-inducing gene 1 protein; Suppressor of K (+) transport growth defect 1; Protein SKD1; VPS4B; SKD1; VPS42; MIG1

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) . VPS4A/B are required for the exosomal release of SDCBP, CD63 and syndecan.

1. Akiyama, K., Yokota, K., Kagawa, S., Shimbara, N., Tamura, T., Akioka, H., Nothwang, H. G., Noda, C., Tanaka, K., Ichihara, A. cDNA cloning and interferon gamma down-regulation of proteasomal subunits X and Y. Science 265: 1231-1234, 1994. 2. Belich, M. P., Glynne, R. J., Senger, G., Sheer, D., Trowsdale, J. Proteasome components with reciprocal expression to that of the MHC-encoded LMP proteins. Curr. Biol. 4: 769-776, 1994. 3. McCusker, D., Jones, T., Sheer, D., Trowsdale, J. Genetic relationships of the genes encoding the human proteasome beta subunits and the proteasome PA28 complex. Genomics 45: 362-367, 1997.

Store at -20°C for one year from date of receipt. After reconstitution, at 4°C for one month. It can also be aliquotted and stored frozen at -20°C for six months. Avoid repeated freeze-thaw cycles.