Sulfhydryl oxidase 1 (QSOX1)
The protein contains 747 amino acids for an estimated molecular weight of 82578 Da.
Catalyzes the oxidation of sulfhydryl groups in peptide and protein thiols to disulfides with the reduction of oxygen to hydrogen peroxide (PubMed:17331072, PubMed:18393449, PubMed:23704371, PubMed:30367560, PubMed:23867277). Plays a role in disulfide bond formation in a variety of extracellular proteins (PubMed:17331072, PubMed:30367560, PubMed:22801504, PubMed:23867277). In fibroblasts, required for normal incorporation of laminin into the extracellular matrix, and thereby for normal cell-cell adhesion and cell migration (PubMed:23704371, PubMed:30367560, PubMed:23867277). (updated: May 8, 2019)
Protein identification was indicated in the following studies:
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.
This protein is predicted to be membranous by TOPCONS.
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Biological Process
Cell redox homeostasis
Cellular protein metabolic process
Extracellular matrix assembly
Negative regulation of macroautophagy
Neutrophil degranulation
Platelet degranulation
Post-translational protein modification
Protein folding
Cellular Component
Endoplasmic reticulum lumen
Extracellular exosome
Extracellular region
Extracellular space
Golgi apparatus
Golgi membrane
Integral component of Golgi membrane
Intercellular bridge
Intracellular membrane-bounded organelle
Obsolete cell
Platelet alpha granule lumen
Specific granule lumen
Tertiary granule lumen
The reference OMIM entry for this protein is 603120
Quiescin q6 sulfhydryl oxidase 1; qsox1
Quiescin q6; qscn6
Q6
CLONING
To identify genes that might play a role in the transition into quiescence and in its maintenance, Coppock et al. (1993) isolated human embryo lung fibroblast cDNAs that were expressed at a higher level in quiescent cells than in logarithmically growing cells. Several partial cDNAs corresponded to the QSOX1 gene, which the authors called Q6. Northern blot analysis revealed that Q6 is expressed as 3- and 4-kb mRNAs in embryo lung fibroblasts. By screening human lung fibroblast and placenta cDNA libraries, Coppock et al. (1998) cloned QSOX1, which they called QSCN6. QSOX1 contains a putative signal sequence, a thioredoxin (TXN; 187700) motif, and a yeast ERV1 (GFER; 600924) domain. Wittke et al. (2003) noted that the 747-amino acid protein shares 41.2% identity with QSOX2 (612860) and that both proteins contain conserved Q6-like regions and a C-terminal transmembrane domain.GENE STRUCTURE
Wittke et al. (2003) determined that the QSOX1 gene contains 12 exons.GENE FUNCTION
QSOX1 is an atypical disulfide catalyst, localized to the Golgi apparatus or secreted from cells. Ilani et al. (2013) examined the physiologic function for extracellular catalysis of de novo disulfide bond formation by QSOX1. QSOX1 activity was required for incorporation of laminin (see 150320) into the extracellular matrix (ECM) synthesized by fibroblasts, and ECM produced without QSOX1 was defective in supporting cell-matrix adhesion. Ilani et al. (2013) developed an inhibitory monoclonal antibody against QSOX1 that could modulate ECM properties and undermine cell migration.BIOCHEMICAL FEATURES
- Crystal Structure Alon et al. (2012) presented the first crystal structure of an intact QSOX enzyme, derived from a trypanosome parasite. Notably, sequential sites in the disulfide relay were found more than 40 angstroms apart in this structure, too far for direct disulfide transfer. To resolve this puzzle, Alon et al. (2012) trapped and crystallized an intermediate in the disulfide hand-off, which showed a 165-degree domain rotation relative to the original structure, bringing the 2 active sites within disulfide-bonding distance. The comparable structure of a mammalian QSOX enzyme, which they also presented, showed further biochemical features that facilitate disulfide transfer in metazoan orthologs. Finally, Alon et al. (2012) quantified the contribution of concatenation to QSOX activity, providing general lessons for the understanding of multidomain enzymes and the design of new catalytic relays.MAPPING
By FISH analysis, Coppock et al. (1998) mapped the QSOX1 gene to chromosome 1q24. ... More on the omim web site
May 11, 2019: Protein entry updated
Automatic update: Entry updated from uniprot information.
Oct. 20, 2018: Protein entry updated
Automatic update: OMIM entry 603120 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).