QSOX1

Quiescin sulfhydryl oxidase 1 is an enzyme that in humans is encoded by the QSOX1 gene.^[5][6][7]

QSOX1
Available structures PDB Ortholog search: PDBe RCSB List of PDB id codes 3LLI, 3LLK, 3Q6O, 4IJ3
Identifiers
Aliases	QSOX1, Q6, QSCN6, quiescin sulfhydryl oxidase 1
External IDs	OMIM: 603120; MGI: 1330818; HomoloGene: 37690; GeneCards: QSOX1; OMA:QSOX1 - orthologs
Gene location (Human) Chr. Chromosome 1 (human)[1] Band 1q25.2 Start 180,154,834 bp[1] End 180,204,030 bp[1]
Gene location (Mouse) Chr. Chromosome 1 (mouse)[2] Band 1|1 G3 Start 155,651,775 bp[2] End 155,688,635 bp[2]
RNA expression pattern Bgee Human Mouse (ortholog) Top expressed in stromal cell of endometrium gallbladder right auricle of heart left testis right testis right ovary upper lobe of left lung left ovary right lung body of stomach Top expressed in seminal vesicula crypt of lieberkuhn of small intestine lip gallbladder esophagus superior surface of tongue spermatocyte granulocyte ascending aorta liver More reference expression data BioGPS More reference expression data
Gene ontology Molecular function oxidoreductase activity thiol oxidase activity protein disulfide isomerase activity flavin-linked sulfhydryl oxidase activity Cellular component integral component of membrane integral component of Golgi membrane Golgi membrane Golgi apparatus extracellular exosome intracellular membrane-bounded organelle membrane intercellular bridge extracellular region platelet alpha granule lumen extracellular space specific granule lumen tertiary granule lumen endoplasmic reticulum lumen Biological process negative regulation of macroautophagy cell redox homeostasis platelet degranulation neutrophil degranulation post-translational protein modification Sources:Amigo / QuickGO
Orthologs Species Human Mouse Entrez 5768 104009 Ensembl ENSG00000116260 ENSMUSG00000033684 UniProt O00391 Q8BND5 RefSeq (mRNA) NM_002826 NM_001004128 NM_001024945 NM_023268 RefSeq (protein) NP_001004128 NP_002817 NP_001020116 NP_075757 Location (UCSC) Chr 1: 180.15 – 180.2 Mb Chr 1: 155.65 – 155.69 Mb PubMed search [3] [4]
Wikidata
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This gene encodes an enzyme that is localized primarily to the Golgi apparatus and secreted fluids.^[8] QSOX1 is a multi-domain disulfide catalyst. Unlike other disulfide catalysts, QSOX1 can both generate disulfides de novo and catalyze dithiol/disulfide exchange. The de novo disulfide bond formation is catalyzed by the ERV1 domain that contains a FAD co-factor that allows depositions of electrons onto the terminal electron acceptor, typically molecular oxygen. The dithiol/disulfide exchange is catalyzed by the thioredoxin domain. The two domains are linked together by a flexible linker that allows the thioredoxin domain to first interact with the substrate protein and then regenerate by ERV1 domain.^[9]

QSOX1 gene expression is induced as fibroblasts begin to exit the proliferative cycle and enter quiescence,^[10][11] suggesting that this gene plays an important role in growth regulation. In fibroblasts QSOX1 is required for normal incorporation of laminin into the extracellular matrix, and thereby for normal cell-cell adhesion and cell migration.^[12]

Two transcript variants encoding two different isoforms have been found for this gene.^[13][7] The two isoforms have different tissue distribution and in addition isoform 1 has a transmembrane helix in the carboxy terminal while isoform 2 is a secreted soluble protein.