Disease relevance of PSMB5

• 5. Similar results were obtained in 50 hospitalized patients without cardiac disease; two of these patients had both an MB2 activity and an MB2/MB1 ratio greater than the cutoff values [1].
• With use of a previously validated assay, the plasma kinetics of the myocardial subform (MB2) and the plasma-modified subform (MB1) were determined in blood samples obtained from 56 patients with acute Q wave myocardial infarction: 33 patients who received thrombolytic therapy (group A) and 23 patients managed conservatively (group B) [2].
• The MB2/MB1 ratio was significantly higher in group A patients than in group B patients between 2 and 10 h after the onset of infarction [2].
• We have performed a single blind trial to assess the value of the monoclonal antibodies MB1 and MT1 in lymphoma classification [3].
• Immunohistochemical staining of non-Hodgkin's lymphoma in paraffin sections using the MB1 and MT1 monoclonal antibodies [3].

High impact information on PSMB5

• However, the turnover of c-Myc is largely dependent on phosphorylation of threonine-58 and serine-62 in MB1, residues that are often mutated in cancer [4].
• To study the fate and role of these cells during the first 2.5-4.5 days of incubation, we constructed yolk sac chimeras (a chick embryo grafted on a quail yolk sac and vice versa) and immunostained them with antibodies specific to cells of quail hemangioblastic lineage (MB1 and QH1) [5].
• In addition to homologues of the human genes PSMB5 through PSMB9, two new genes, PSMB11 and PSMB12, have been found for which there are no known corresponding genes in humans [6].
• Ritonavir is a reversible effector of proteasome activity that protected the subunits MB-1 (X) and/or LMP7 from covalent active site modification with the vinyl sulfone inhibitor(125)I-NLVS, suggesting that they are the prime targets for competitive inhibition by Ritonavir [7].
• CONCLUSIONS: We suggest that the subtle phenotype of LMP-deficient cell lines results from the compensatory expression in these lines of two other proteasome subunits, MB1 and Delta [8].

Chemical compound and disease context of PSMB5

• This study shows that MB1, LN1 and LN2 are fairly but not entirely specific for B-cells in the non-Hodgkin's lymphomas, but are not very sensitive when applied to formalin-fixed tissues [9].
• We explored the use of alternative adjuvant formulations (poly lactide co-glycolide (PLG) microparticles, MF59 emulsion, CAP and l-tyrosine suspension) in comparison with five different vaccine antigens--namely, diphtheria toxoid (DT), tetanus toxoid (TT), HBsAg, Men C conjugate and MB1 [10].

Biological context of PSMB5

• Genes encoding the alpha and beta subunits of the PA28 complex were found closely linked on chromosome band 14q11.2, within 1 Mb of the beta proteasome locus PSMB5 (beta5 hs, MB1, X) [11].
• Psmb5 is made up of three exons, spanning approximately 5 kilobases [12].
• As well as the Psmb5 gene, the mouse genome contains a processed pseudogene designated Psmb5-ps [12].
• These proteins contain an active site of proteolysis, and LMP7 replaces PSMB5 as a component of the 20S proteasome after stimulation of cells by interferon-gamma [13].
• The LMP7 and PSMB5 genes were created through an ancient gene duplication event of their ancestral locus [13].

Anatomical context of PSMB5

• Replacement of PSMB5 by LMP7 changes the profile of the products of 20S proteasome processing, predisposing digested peptides for transport to and display by the immune system [13].
• PURPOSE: To determine whether the overexpression of the proteasome catalytic beta5 subunit (PSMB5) can induce the expression of the catalytic subunits beta1 and beta2, enhance proteasome activity, and exert a cytoprotective effect in lens epithelial cells [14].
• Expression of the MB1 and delta genes is reciprocal to that of the LMP genes: MB1 and delta are up-regulated in mutant cell lines lacking LMPs and down-regulated in the presence of gamma-interferon [8].
• These replace the constitutively expressed active site subunits of the proteasome (delta, MB1, and Z) leading to a marked change in the cleavage preference of the proteasome and the production of T-cell epitopes [15].
• Most B lymphocytes expressed antigens associated with HLA-DR, and the specificities SB2, SB3, MB1, MB3, MT2, and MT3 were also present [16].

Associations of PSMB5 with chemical compounds

• These results were confirmed by fluorescent in situ hybridization analysis that localized Psmb5 to band C2 to proximal D1 of chromosome 14 and Psmb5-ps to band D of chromosome 11 [12].
• No evidence of mutations of the PSMB5 (beta-5 subunit of proteasome) in a case of myeloma with clinical resistance to Bortezomib [17].
• Prior to ablation and at 30 min, 1, 2, 6, and 12 h following the procedure, blood samples were taken to measure troponin-T and creatine kinase-MB concentrations, and the separation of creatine kinase isoforms (MM3/MM1 and MB2/MB1 ratios) [18].

Regulatory relationships of PSMB5

• Coexpression of Lmp2 and Lmp7 with the constitutively expressed subunits delta and MB1 was demonstrated in the BL lines by immunoprecipitation and two-dimensional gel fractionation of the 20S proteasomes [19].

Other interactions of PSMB5

• Collectively, these results indicate that expression of proteasome subunit PSMB5 is modulated by bifunctional enzyme inducers in a manner independent of the AhR/Arnt-XRE pathway but dependent upon the Nrf2-ARE pathway [20].
• Neither anti-LMP2 nor anti-LMP7 sera displayed cross-reactivity with the homologous proteasome subunits Delta and MB1 [21].

Analytical, diagnostic and therapeutic context of PSMB5

• Sixty cases of non-Hodgkin's lymphoma (NHL) were stained with MB1 and MT1 using an indirect immunoperoxidase technique in paraffin sections [3].
• Patients in the PTCA group showed an association between ischemic ST segment changes lasting > 3 min and a transient increase in the MB2/MB1 ratio; however, all had total CK-MB activity within normal limits [22].
• Routine coronary angiography subjects had no significant change in MB2/MB1 [22].
• Three of the MAbs obtained, MB1, MB2 and MB3, were specific to MDV by immunofluorescence test [23].
• After thoracotomy, MB2/MB1 was increased only in elderly patients (n = 5) with risk factors for ischemic heart disease; total CK-MB activity was increased in only three of these [22].

References