Proteasome assembly chaperone 1 (PSMG1)
The protein contains 288 amino acids for an estimated molecular weight of 32854 Da.
Chaperone protein which promotes assembly of the 20S proteasome as part of a heterodimer with PSMG2. The PSMG1-PSMG2 heterodimer binds to the PSMA5 and PSMA7 proteasome subunits, promotes assembly of the proteasome alpha subunits into the heteroheptameric alpha ring and prevents alpha ring dimerization. (updated: March 4, 2015)
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.
- 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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| Variant | Description |
|---|---|
| dbSNP:rs8131611 |
Biological Process
Cerebellar granule cell precursor proliferation
Chaperone-mediated protein complex assembly
Proteasome assembly
Proteasome core complex assembly
Cellular Component
Chaperone complex
Cytoplasm
Cytosol
Endoplasmic reticulum
Golgi apparatus
Nucleoplasm
Nucleus
The reference OMIM entry for this protein is 605296
Proteasome-assembling chaperone 1; psmg1
Proteasome assembly chaperone 1; pac1
Down syndrome critical region gene 2; dscr2
Chromosome 21 leucine-rich protein; c21lrp
CLONING
By searching an EST database for genes between markers D21S343 and D21S268 in Down syndrome (190685) critical region 2, Vidal-Taboada et al. (1998) identified DSCR2, which they termed C21LRP (chromosome 21 leucine-rich protein). The deduced 288-amino acid DSCR2 protein contains 2 transmembrane helices. Northern blot analysis detected high expression of a 1.3-kb DSCR2 transcript in testis and in the Jurkat leukemia cell line. RT-PCR analysis detected DSCR2 mRNA in brain, colon, leukocytes, breast, and testis, as well as in all fetal tissues tested. Vidal-Taboada et al. (2000) cloned the mouse Dscr2 gene and found that it is widely expressed in adult mouse tissues and throughout all stages of mouse embryo development.GENE FUNCTION
Hirano et al. (2005) reported 2 chaperones designated proteasome-assembling chaperone-1 (PAC1) and PAC2 (609702), that are involved in the maturation of the mammalian 20S proteasomes. PAC1 and PAC2 associate as heterodimers with proteasome precursors and are degraded after formation of the 20S proteasome is completed. Overexpression of PAC1 or PAC2 accelerates the formation of precursor proteasomes, whereas knockdown by short interfering RNA impairs it, resulting in poor maturation of 20S proteasomes. Furthermore, Hirano et al. (2005) showed that the PAC complex provides a scaffold for alpha ring formation and keeps the alpha rings competent for the subsequent formation of half-proteasomes. Thus, Hirano et al. (2005) concluded that their results identify a mechanism for the correct assembly of 20S proteasomes.MAPPING
Vidal-Taboada et al. (1998) identified the DSCR2 gene on chromosome 21q22.3. ... More on the omim web site
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 605296 was added.