PSMB9

569816912ENSG00000243594ENSG00000243958ENSG00000239836ENSMUSG00000096727P28065P28076NM_002800NM_148954NM_013585NP_002791NP_038613Proteasome subunit beta type-9 as known as 20S proteasome subunit beta-1i is a protein that in humans is encoded by the PSMB9 gene. Proteasome subunit beta type-9 as known as 20S proteasome subunit beta-1i is a protein that in humans is encoded by the PSMB9 gene. This protein is one of the 17 essential subunits (alpha subunits 1-7, constitutive beta subunits 1-7, and inducible subunits including beta1i, beta2i, beta5i) that contributes to the complete assembly of 20S proteasome complex. In particular, proteasome subunit beta type-5, along with other beta subunits, assemble into two heptameric rings and subsequently a proteolytic chamber for substrate degradation. This protein contains 'Trypsin-like' activity and is capable of cleaving after basic residues of peptide. The eukaryotic proteasome recognized degradable proteins, including damaged proteins for protein quality control purpose or key regulatory protein components for dynamic biological processes. The constitutive subunit beta1, beta2, and beta 5 (systematic nomenclature) can be replaced by their inducible counterparts beta1i, 2i, and 5i when cells are under the treatment of interferon-γ. The resulting proteasome complex becomes the so-called immunoproteasome. An essential function of the modified proteasome complex, the immunoproteasome, is the processing of numerous MHC class-I restricted T cell epitopes. The gene PSMB9 encodes a member of the proteasome B-type family, also known as the T1B family, that is a 20S core beta subunit. This gene is located in the class II region of the MHC (major histocompatibility complex). Expression of this gene is induced by gamma interferon and this gene product replaces catalytic subunit 1 (proteasome beta 6 subunit) in the immunoproteasome. Proteolytic processing is required to generate a mature subunit. Two alternative transcripts encoding different isoforms have been identified; both isoforms are processed to yield the same mature subunit. The human PSMB9 gene has 6 exons and locates at chromosome band 6p21.3.