Sulfhydryl oxidase 2 (QSOX2)
The protein contains 698 amino acids for an estimated molecular weight of 77529 Da.
Catalyzes the oxidation of sulfhydryl groups in peptide and protein thiols to disulfides with the reduction of oxygen to hydrogen peroxide. May contribute to disulfide bond formation in a variety of secreted proteins. Also seems to play a role in regulating the sensitization of neuroblastoma cells for interferon-gamma-induced apoptosis. (updated: July 24, 2007)
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 annotated as membranous in Gene Ontology, is annotated as membranous in UniProt, is predicted to be membranous by TOPCONS.
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| Variant | Description |
|---|---|
| dbSNP:rs12380852 |
The reference OMIM entry for this protein is 612860
Quiescin q6 sulfhydryl oxidase 2; qsox2
Sulfhydryl oxidase, neuroblastoma-derived; soxn
DESCRIPTION
QSOX2 is a member of the sulfhydryl oxidase/quiescin-6 (Q6) family (QSOX1; 603120) that regulates the sensitization of neuroblastoma cells for IFN-gamma (IFNG; 147570)-induced cell death (Wittke et al., 2003).CLONING
Using a functional technical knockout system in a neuroblastoma cell line, followed by database analysis, Wittke et al. (2003) identified QSOX2, which they called SOXN. The deduced 698-amino acid protein has a calculated molecular mass of 77.3 kD and contains a signal sequence, a protein-disulfide-isomerase (PDI)-type thioredoxin domain, a yeast ERV1 (GFER; 600924) domain, a conserved N-glycosylation motif, Q6-like regions, and a C-terminal transmembrane domain. Northern blot analysis of adult and fetal tissues detected 7.5- and 4.6-kb transcripts in all fetal and adult tissues tested with highest expression detected in pancreas, brain, placenta, kidney, heart, and fetal tissues compared to lung, liver, and skeletal muscle. Using cell fractionation and immunohistochemical studies, Wittke et al. (2003) determined that QSOX2 is a membrane-associated protein localized to the plasma membrane in neuroblastoma cells. Upon induction of apoptosis, QSOX2 localized to apoptotic bodies.GENE FUNCTION
Wittke et al. (2003) showed that antisense RNA inhibition of QSOX2 protected Tet21N neuroblastoma cells from cell death but had no effect on IFN gamma-induced suppression of cell growth. QSOX2 mRNA levels rose in response to low serum/MYCN/IFN-gamma induction of apoptosis. Overexpression of QSOX2 sensitized cells to IFN gamma-induced apoptosis. Wittke et al. (2003) suggested that increased QSOX2 was not sufficient to induce cell death, but that its increased expression sensitized cells toward induction of cell death in response to IFN-gamma.GENE STRUCTURE
Wittke et al. (2003) determined that the QSOX2 gene contains 12 exons spanning approximately 32 kb.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, Wittke et al. (2003) mapped the QSOX2 gene to chromosome 9q34.3. ... More on the omim web site
June 30, 2020: Protein entry updated
Automatic update: OMIM entry 612860 was added.
Oct. 19, 2018: Additional information
Initial protein addition to the database. This entry was referenced in Bryk and co-workers. (2017).