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PSMB10

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PSMB10
Identifiers
AliasesPSMB10, LMP10, MECL1, beta2i, proteasome subunit beta 10, proteasome 20S subunit beta 10, PRAAS5
External IDsOMIM: 176847; MGI: 1096380; HomoloGene: 20616; GeneCards: PSMB10; OMA:PSMB10 - orthologs
Orthologs
SpeciesHumanMouse
Entrez

5699

19171

Ensembl

ENSG00000205220

ENSMUSG00000031897

UniProt

P40306

O35955

RefSeq (mRNA)

NM_002801

NM_013640

RefSeq (protein)

NP_002792

NP_038668

Location (UCSC)Chr 16: 67.93 – 67.94 MbChr 8: 106.66 – 106.67 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Proteasome subunit beta type-10 as known as 20S proteasome subunit beta-2i is a protein that in humans is encoded by the PSMB10 gene.[5]

This protein has a major role in the immune system as part of an immunoproteasome that is primarily induced upon infection and formed by replacing constitutive beta subunits with inducible beta subunits which possess specific cleavage properties that aid in the release of peptides necessary for MHC class I antigen presentation.[6] The immunoproteasome appears to have a pivotal role in modulating NFκB signaling.[7]

Structure

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Gene

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This gene PSMB10 encodes a member of the proteasome B-type family, also known as the T1B family, that is a 20S core beta subunit. Proteolytic processing is required to generate a mature subunit. Expression of this gene is induced by gamma interferon, and this gene product replaces catalytic subunit beta2 (proteasome subunit beta type-7) in the immunoproteasome.[8] The human PSMB10 gene has 8 exons and locates at chromosome band 16q22.1.

Protein structure

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The human protein proteasome subunit beta type-8 is 25 kDa in size and composed of 234 amino acids. The calculated theoretical pI of this protein is 6.07.

Complex assembly

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Proteasome subunit beta type-10 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-2i, 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.[9] 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.[10]

The proteasome is a multicatalytic proteinase complex with a highly ordered 20S core structure. This barrel-shaped core structure is composed of 4 axially stacked rings of 28 non-identical subunits: the two end rings are each formed by 7 alpha subunits, and the two central rings are each formed by 7 beta subunits. Three beta subunits (beta1, beta2, beta5) each contains a proteolytic active site and has distinct substrate preferences. Proteasomes are distributed throughout eukaryotic cells at a high concentration and cleave peptides in an ATP/ubiquitin-dependent process in a non-lysosomal pathway.[11][12]

Function

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Protein functions are supported by its tertiary structure and its interaction with associating partners. As one of 28 subunits of 20S proteasome, protein proteasome subunit beta type-2 contributes to form a proteolytic environment for substrate degradation. Evidences of the crystal structures of isolated 20S proteasome complex demonstrate that the two rings of beta subunits form a proteolytic chamber and maintain all their active sites of proteolysis within the chamber.[12] Concomitantly, the rings of alpha subunits form the entrance for substrates entering the proteolytic chamber. In an inactivated 20S proteasome complex, the gate into the internal proteolytic chamber are guarded by the N-terminal tails of specific alpha-subunit. This unique structure design prevents random encounter between proteolytic active sites and protein substrate, which makes protein degradation a well-regulated process.[13][14] 20S proteasome complex, by itself, is usually functionally inactive. The proteolytic capacity of 20S core particle (CP) can be activated when CP associates with one or two regulatory particles (RP) on one or both side of alpha rings. These regulatory particles include 19S proteasome complexes, 11S proteasome complex, etc. Following the CP-RP association, the confirmation of certain alpha subunits will change and consequently cause the opening of substrate entrance gate. Besides RPs, the 20S proteasomes can also be effectively activated by other mild chemical treatments, such as exposure to low levels of sodium dodecylsulfate (SDS) or NP-14.[14][15]

The 20S proteasome subunit beta-2i (systematic nomenclature) is originally expressed as a precursor with 273 amino acids. The fragment of 39 amino acids at peptide N-terminal is essential for proper protein folding and subsequent complex assembly. At the end-stage of complex assembly, the N-terminal fragment of beta2i subunit is cleaved, forming the mature beta2i subunit of 20S complex.[16] During the basal assembly, and proteolytic processing is required to generate a mature subunit. The subunit beta5i only presents in the immunoproteasome and is replaced by subunit beta5(proteasome beta 5 subunit) in constitutive 20S proteasome complex. This protein has an important function in the immune system as part of an immunoproteasome which possess specific cleavage properties that aid in the release of peptides necessary for MHC class I antigen presentation.[6]

Clinical significance

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The proteasome and its subunits are of clinical significance for at least two reasons: (1) a compromised complex assembly or a dysfunctional proteasome can be associated with the underlying pathophysiology of specific diseases, and (2) they can be exploited as drug targets for therapeutic interventions. More recently, more effort has been made to consider the proteasome for the development of novel diagnostic markers and strategies. An improved and comprehensive understanding of the pathophysiology of the proteasome should lead to clinical applications in the future.

The proteasomes form a pivotal component for the ubiquitin–proteasome system (UPS) [17] and corresponding cellular Protein Quality Control (PQC). Protein ubiquitination and subsequent proteolysis and degradation by the proteasome are important mechanisms in the regulation of the cell cycle, cell growth and differentiation, gene transcription, signal transduction and apoptosis.[18] Subsequently, a compromised proteasome complex assembly and function lead to reduced proteolytic activities and the accumulation of damaged or misfolded protein species. Such protein accumulation may contribute to the pathogenesis and phenotypic characteristics in neurodegenerative diseases,[19][20] cardiovascular diseases,[21][22][23] inflammatory responses and autoimmune diseases,[24] and systemic DNA damage responses leading to malignancies.[25]

Several experimental and clinical studies have indicated that aberrations and deregulations of the UPS contribute to the pathogenesis of several neurodegenerative and myodegenerative disorders, including Alzheimer's disease,[26] Parkinson's disease[27] and Pick's disease,[28] Amyotrophic lateral sclerosis (ALS),[28] Huntington's disease,[27] Creutzfeldt–Jakob disease,[29] and motor neuron diseases, polyglutamine (PolyQ) diseases, Muscular dystrophies[30] and several rare forms of neurodegenerative diseases associated with dementia.[31] As part of the ubiquitin–proteasome system (UPS), the proteasome maintains cardiac protein homeostasis and thus plays a significant role in cardiac ischemic injury,[32] ventricular hypertrophy[33] and heart failure.[34] Additionally, evidence is accumulating that the UPS plays an essential role in malignant transformation. UPS proteolysis plays a major role in responses of cancer cells to stimulatory signals that are critical for the development of cancer. Accordingly, gene expression by degradation of transcription factors, such as p53, c-jun, c-Fos, NF-κB, c-Myc, HIF-1α, MATα2, STAT3, sterol-regulated element-binding proteins and androgen receptors are all controlled by the UPS and thus involved in the development of various malignancies.[35] Moreover, the UPS regulates the degradation of tumor suppressor gene products such as adenomatous polyposis coli (APC) in colorectal cancer, retinoblastoma (Rb). and von Hippel–Lindau tumor suppressor (VHL), as well as a number of proto-oncogenes (Raf, Myc, Myb, Rel, Src, Mos, ABL). The UPS is also involved in the regulation of inflammatory responses. This activity is usually attributed to the role of proteasomes in the activation of NF-κB which further regulates the expression of pro inflammatory cytokines such as TNF-α, IL-β, IL-8, adhesion molecules (ICAM-1, VCAM-1, P-selectin) and prostaglandins and nitric oxide (NO).[24] Additionally, the UPS also plays a role in inflammatory responses as regulators of leukocyte proliferation, mainly through proteolysis of cyclines and the degradation of CDK inhibitors.[36] Lastly, autoimmune disease patients with SLE, Sjögren syndrome and rheumatoid arthritis (RA) predominantly exhibit circulating proteasomes which can be applied as clinical biomarkers.[37]

During the antigen processing for the major histocompatibility complex (MHC) class-I, the proteasome is the major degradation machinery that degrades the antigen and present the resulting peptides to cytotoxic T lymphocytes.[38][39] The immunoproteasome has been considered playing a critical role in improving the quality and quantity of generated class-I ligands.

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000205220 – Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000031897 – Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Larsen F, Solheim J, Kristensen T, Kolstø AB, Prydz H (Oct 1993). "A tight cluster of five unrelated human genes on chromosome 16q22.1". Human Molecular Genetics. 2 (10): 1589–95. doi:10.1093/hmg/2.10.1589. PMID 8268911.
  6. ^ a b Kasthuri SR, Umasuthan N, Whang I, Lim BS, Jung HB, Oh MJ, Jung SJ, Yeo SY, Kim SY, Lee J (Aug 2014). "Molecular characterization and expressional affirmation of the beta proteasome subunit cluster in rock bream immune defense". Molecular Biology Reports. 41 (8): 5413–27. doi:10.1007/s11033-014-3413-1. PMID 24867079. S2CID 16946886.
  7. ^ Maldonado M, Kapphahn RJ, Terluk MR, Heuss ND, Yuan C, Gregerson DS, Ferrington DA (2013). "Immunoproteasome deficiency modifies the alternative pathway of NFκB signaling". PLOS ONE. 8 (2): e56187. Bibcode:2013PLoSO...856187M. doi:10.1371/journal.pone.0056187. PMC 3572990. PMID 23457524.
  8. ^ "Entrez Gene: PSMB10 proteasome (prosome, macropain) subunit, beta type, 10".
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  16. ^ Yang Y, Früh K, Ahn K, Peterson PA (Nov 1995). "In vivo assembly of the proteasomal complexes, implications for antigen processing". The Journal of Biological Chemistry. 270 (46): 27687–94. doi:10.1074/jbc.270.46.27687. PMID 7499235.
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  18. ^ Goldberg AL, Stein R, Adams J (Aug 1995). "New insights into proteasome function: from archaebacteria to drug development". Chemistry & Biology. 2 (8): 503–8. doi:10.1016/1074-5521(95)90182-5. PMID 9383453.
  19. ^ Sulistio YA, Heese K (Jan 2015). "The Ubiquitin-Proteasome System and Molecular Chaperone Deregulation in Alzheimer's Disease". Molecular Neurobiology. 53 (2): 905–31. doi:10.1007/s12035-014-9063-4. PMID 25561438. S2CID 14103185.
  20. ^ Ortega Z, Lucas JJ (2014). "Ubiquitin-proteasome system involvement in Huntington's disease". Frontiers in Molecular Neuroscience. 7: 77. doi:10.3389/fnmol.2014.00077. PMC 4179678. PMID 25324717.
  21. ^ Sandri M, Robbins J (Jun 2014). "Proteotoxicity: an underappreciated pathology in cardiac disease". Journal of Molecular and Cellular Cardiology. 71: 3–10. doi:10.1016/j.yjmcc.2013.12.015. PMC 4011959. PMID 24380730.
  22. ^ Drews O, Taegtmeyer H (Dec 2014). "Targeting the ubiquitin-proteasome system in heart disease: the basis for new therapeutic strategies". Antioxidants & Redox Signaling. 21 (17): 2322–43. doi:10.1089/ars.2013.5823. PMC 4241867. PMID 25133688.
  23. ^ Wang ZV, Hill JA (Feb 2015). "Protein quality control and metabolism: bidirectional control in the heart". Cell Metabolism. 21 (2): 215–26. doi:10.1016/j.cmet.2015.01.016. PMC 4317573. PMID 25651176.
  24. ^ a b Karin M, Delhase M (Feb 2000). "The I kappa B kinase (IKK) and NF-kappa B: key elements of proinflammatory signalling". Seminars in Immunology. 12 (1): 85–98. doi:10.1006/smim.2000.0210. PMID 10723801.
  25. ^ Ermolaeva MA, Dakhovnik A, Schumacher B (Jan 2015). "Quality control mechanisms in cellular and systemic DNA damage responses". Ageing Research Reviews. 23 (Pt A): 3–11. doi:10.1016/j.arr.2014.12.009. PMC 4886828. PMID 25560147.
  26. ^ Checler F, da Costa CA, Ancolio K, Chevallier N, Lopez-Perez E, Marambaud P (Jul 2000). "Role of the proteasome in Alzheimer's disease". Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease. 1502 (1): 133–8. doi:10.1016/s0925-4439(00)00039-9. PMID 10899438.
  27. ^ a b Chung KK, Dawson VL, Dawson TM (Nov 2001). "The role of the ubiquitin-proteasomal pathway in Parkinson's disease and other neurodegenerative disorders". Trends in Neurosciences. 24 (11 Suppl): S7–14. doi:10.1016/s0166-2236(00)01998-6. PMID 11881748. S2CID 2211658.
  28. ^ a b Ikeda K, Akiyama H, Arai T, Ueno H, Tsuchiya K, Kosaka K (Jul 2002). "Morphometrical reappraisal of motor neuron system of Pick's disease and amyotrophic lateral sclerosis with dementia". Acta Neuropathologica. 104 (1): 21–8. doi:10.1007/s00401-001-0513-5. PMID 12070660. S2CID 22396490.
  29. ^ Manaka H, Kato T, Kurita K, Katagiri T, Shikama Y, Kujirai K, Kawanami T, Suzuki Y, Nihei K, Sasaki H (May 1992). "Marked increase in cerebrospinal fluid ubiquitin in Creutzfeldt–Jakob disease". Neuroscience Letters. 139 (1): 47–9. doi:10.1016/0304-3940(92)90854-z. PMID 1328965. S2CID 28190967.
  30. ^ Mathews KD, Moore SA (Jan 2003). "Limb-girdle muscular dystrophy". Current Neurology and Neuroscience Reports. 3 (1): 78–85. doi:10.1007/s11910-003-0042-9. PMID 12507416. S2CID 5780576.
  31. ^ Mayer RJ (Mar 2003). "From neurodegeneration to neurohomeostasis: the role of ubiquitin". Drug News & Perspectives. 16 (2): 103–8. doi:10.1358/dnp.2003.16.2.829327. PMID 12792671.
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  33. ^ Predmore JM, Wang P, Davis F, Bartolone S, Westfall MV, Dyke DB, Pagani F, Powell SR, Day SM (Mar 2010). "Ubiquitin proteasome dysfunction in human hypertrophic and dilated cardiomyopathies". Circulation. 121 (8): 997–1004. doi:10.1161/CIRCULATIONAHA.109.904557. PMC 2857348. PMID 20159828.
  34. ^ Powell SR (Jul 2006). "The ubiquitin–proteasome system in cardiac physiology and pathology". American Journal of Physiology. Heart and Circulatory Physiology. 291 (1): H1–H19. doi:10.1152/ajpheart.00062.2006. PMID 16501026. S2CID 7073263.
  35. ^ Adams J (Apr 2003). "Potential for proteasome inhibition in the treatment of cancer". Drug Discovery Today. 8 (7): 307–15. doi:10.1016/s1359-6446(03)02647-3. PMID 12654543.
  36. ^ Ben-Neriah Y (Jan 2002). "Regulatory functions of ubiquitination in the immune system". Nature Immunology. 3 (1): 20–6. doi:10.1038/ni0102-20. PMID 11753406. S2CID 26973319.
  37. ^ Egerer K, Kuckelkorn U, Rudolph PE, Rückert JC, Dörner T, Burmester GR, Kloetzel PM, Feist E (Oct 2002). "Circulating proteasomes are markers of cell damage and immunologic activity in autoimmune diseases". The Journal of Rheumatology. 29 (10): 2045–52. PMID 12375310.
  38. ^ Basler M, Lauer C, Beck U, Groettrup M (Nov 2009). "The proteasome inhibitor bortezomib enhances the susceptibility to viral infection". Journal of Immunology. 183 (10): 6145–50. doi:10.4049/jimmunol.0901596. PMID 19841190.
  39. ^ Rock KL, Gramm C, Rothstein L, Clark K, Stein R, Dick L, Hwang D, Goldberg AL (Sep 1994). "Inhibitors of the proteasome block the degradation of most cell proteins and the generation of peptides presented on MHC class I molecules". Cell. 78 (5): 761–71. doi:10.1016/s0092-8674(94)90462-6. PMID 8087844. S2CID 22262916.

Further reading

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