Proteasome subunit alpha type-7 (PSMA7)
The protein contains 248 amino acids for an estimated molecular weight of 27887 Da.
Component of the 20S core proteasome complex involved in the proteolytic degradation of most intracellular proteins. This complex plays numerous essential roles within the cell by associating with different regulatory particles. Associated with two 19S regulatory particles, forms the 26S proteasome and thus participates in the ATP-dependent degradation of ubiquitinated proteins. The 26S proteasome plays a key role in the maintenance of protein homeostasis by removing misfolded or damaged proteins that could impair cellular functions, and by removing proteins whose functions are no longer required. Associated with the PA200 or PA28, the 20S proteasome mediates ubiquitin-independent protein degradation. This type of proteolysis is required in several pathways including spermatogenesis (20S-PA200 complex) or generation of a subset of MHC class I-presented antigenic peptides (20S-PA28 complex). Inhibits the transactivation function of HIF-1A under both normoxic and hypoxia-mimicking conditions. The interaction with EMAP2 increases the proteasome-mediated HIF-1A degradation under the hypoxic conditions. Plays a role in hepatitis C virus internal ribosome entry site-mediated translation. Mediates nuclear translocation of the androgen receptor (AR) and thereby enhances androgen-mediated transactivation. Promotes MAVS degradation and thereby negatively regulates MAVS-mediated innate immune response. (updated: Jan. 31, 2018)
Protein identification was indicated in the following studies:
- Goodman and co-workers. (2013) The proteomics and interactomics of human erythrocytes. Exp Biol Med (Maywood) 238(5), 509-518.
- Lange and co-workers. (2014) Annotating N termini for the human proteome project: N termini and Nα-acetylation status differentiate stable cleaved protein species from degradation remnants in the human erythrocyte proteome. J Proteome Res. 13(4), 2028-2044.
- Hegedűs and co-workers. (2015) Inconsistencies in the red blood cell membrane proteome analysis: generation of a database for research and diagnostic applications. Database (Oxford) 1-8.
- Wilson and co-workers. (2016) Comparison of the Proteome of Adult and Cord Erythroid Cells, and Changes in the Proteome Following Reticulocyte Maturation. Mol Cell Proteomics. 15(6), 1938-1946.
- Bryk and co-workers. (2017) Quantitative Analysis of Human Red Blood Cell Proteome. J Proteome Res. 16(8), 2752-2761.
- D'Alessandro and co-workers. (2017) Red blood cell proteomics update: is there more to discover? Blood Transfus. 15(2), 182-187.
- Chu and co-workers. (2018) Quantitative mass spectrometry of human reticulocytes reveal proteome-wide modifications during maturation. Br J Haematol. 180(1), 118-133.
Methods
The following articles were analysed to gather the proteome content of erythrocytes.
The gene or protein list provided in the studies were processed using the ID mapping API of Uniprot in September 2018. The number of proteins identified and mapped without ambiguity in these studies is indicated below.
Only Swiss-Prot entries (reviewed) were considered for protein evidence assignation.
| Publication | Identification 1 | Uniprot mapping 2 | Not mapped / Obsolete | TrEMBL | Swiss-Prot |
|---|---|---|---|---|---|
| Goodman (2013) | 2289 (gene list) | 2278 | 53 | 20599 | 2269 |
| Lange (2014) | 1234 | 1234 | 7 | 28 | 1224 |
| Hegedus (2015) | 2638 | 2622 | 0 | 235 | 2387 |
| Wilson (2016) | 1658 | 1528 | 170 | 291 | 1068 |
| d'Alessandro (2017) | 1826 | 1817 | 2 | 0 | 1815 |
| Bryk (2017) | 2090 | 2060 | 10 | 108 | 1942 |
| Chu (2018) | 1853 | 1804 | 55 | 362 | 1387 |
1 as available in the article and/or in supplementary material
2 uniprot mapping returns all protein isoforms as one entry
The compilation of older studies can be retrieved from the Red Blood Cell Collection database.
The data and differentiation stages presented below come from the proteomic study and analysis performed by our partners of the GReX consortium, more details are available in their published work.
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Biological Process
Anaphase-promoting complex-dependent catabolic process
Antigen processing and presentation of exogenous peptide antigen via MHC class I
Antigen processing and presentation of exogenous peptide antigen via MHC class I, TAP-dependent
Antigen processing and presentation of peptide antigen via MHC class I
Apoptotic process
Cellular nitrogen compound metabolic process
DNA damage response, signal transduction by p53 class mediator resulting in cell cycle arrest
Fc-epsilon receptor signaling pathway
G1/S transition of mitotic cell cycle
Gene expression
Interleukin-1-mediated signaling pathway
MAPK cascade
Mitotic cell cycle
Negative regulation of apoptotic process
Negative regulation of canonical Wnt signaling pathway
Negative regulation of G2/M transition of mitotic cell cycle
NIK/NF-kappaB signaling
Obsolete negative regulation of ubiquitin-protein ligase activity involved in mitotic cell cycle
Obsolete positive regulation of ubiquitin-protein ligase activity involved in regulation of mitotic cell cycle transition
Obsolete regulation of ubiquitin-protein ligase activity involved in mitotic cell cycle
Positive regulation of canonical Wnt signaling pathway
Post-translational protein modification
Pre-replicative complex assembly
Proteasomal protein catabolic process
Proteasomal ubiquitin-independent protein catabolic process
Proteasome-mediated ubiquitin-dependent protein catabolic process
Protein deubiquitination
Protein polyubiquitination
Regulation of apoptotic process
Regulation of cellular amino acid metabolic process
Regulation of hematopoietic stem cell differentiation
Regulation of mitotic cell cycle phase transition
Regulation of mRNA stability
Regulation of transcription from RNA polymerase II promoter in response to hypoxia
SCF-dependent proteasomal ubiquitin-dependent protein catabolic process
Small molecule metabolic process
Stimulatory C-type lectin receptor signaling pathway
T cell receptor signaling pathway
Transmembrane transport
Tumor necrosis factor-mediated signaling pathway
Ubiquitin-dependent protein catabolic process
Viral process
Wnt signaling pathway, planar cell polarity pathway
Cellular Component
Cytoplasm
Cytosol
Extracellular exosome
Nucleoplasm
Nucleus
Postsynapse
Proteasome complex
Proteasome core complex
Proteasome core complex, alpha-subunit complex
Molecular Function
Endopeptidase activity
Identical protein binding
Threonine-type endopeptidase activity
The reference OMIM entry for this protein is 606607
Proteasome subunit, alpha-type, 7; psma7
Xapc7
Proteasome subunit alpha-4
CLONING
The hepatitis B virus X (HBX) protein is a well-conserved 16-kD phosphoprotein expressed in both nucleus and cytoplasm. It is critical for the life cycle of the virus. HBX message is detectable in infected liver, as are antibodies to the less-detectable protein. Using a yeast 2-hybrid screen of a HeLa cell cDNA library with HBX as the probe, followed by further probing of the HeLa cell library, Huang et al. (1996) obtained a cDNA encoding PSMA7, which they termed XAPC7. The deduced 248-amino acid PSMA7 protein is 33% identical to HC8 (PSMA3; 176843) and has higher homology with Drosophila and Arabidopsis proteasome subunits. Northern blot analysis revealed expression of a 1.0-kb PSMA7 transcript in several human cell lines. Western blot analysis showed that PSMA7 is expressed as a 28-kD proteasome subunit protein.MAPPING
Gross (2013) mapped the PSMA7 gene to chromosome 20q13.33 based on an alignment of the PSMA7 sequence (GenBank GENBANK AF022815) with the genomic sequence (GRCh37).GENE FUNCTION
Huang et al. (1996) found that residues 188 to 198 in the C terminus of PSMA7, but not these residues in other proteasome subunits, specifically interacted with HBX and that the N terminus of HBX, which is required for its transactivation function, was not necessary for its interaction with PSMA7. Luciferase reporter assays demonstrated that antisense PSMA7 blocked the transactivation function of HBX. Huang et al. (1996) proposed that HBX, by interacting with PSMA7, may interfere with the activities of the proteasome complex. Using a yeast 2-hybrid screen of a fetal brain cDNA library with parkin (PARK2; 602544) and 2 parkin mutants as baits, Dachsel et al. (2005) isolated PSMA7, which they termed alpha-4. Coimmunoprecipitation experiments showed that the interaction occurred between residues 179 to 248 of PSMA7 and the C terminus of PARKIN, including the IBR-RING2 motif. Liu et al. (2006) found that ABL (ABL1; 189980) and ARG (ABL2; 164690) tyrosine kinases associated with and phosphorylated PSMA7 on tyr153, leading to reduced proteasome-dependent proteolysis. Cells expressing a phosphorylation mutant of PSMA7 displayed impaired G1/S transition and S/G2 progression. Oxidative stress and ionizing irradiation resulted in increased formation of ABL-PSMA7 complexes and PSMA7 phosphorylation. Liu et al. (2006) concluded that phosphorylation of PSMA7 regulates proteasome activity.MOLECULAR GENETICS
For discussion of mutation in the PSMA7 gene as a possible cause of an intellectual disability phenotype, see 606607.0001. ... More on the omim web site
Feb. 10, 2018: Protein entry updated
Automatic update: Entry updated from uniprot information.
Feb. 2, 2018: Protein entry updated
Automatic update: Uniprot description updated
Dec. 19, 2017: Protein entry updated
Automatic update: Uniprot description updated
Nov. 23, 2017: Protein entry updated
Automatic update: Uniprot description updated
March 16, 2016: Protein entry updated
Automatic update: OMIM entry 606607 was added.