CYBB Gene (Cytochrome B-245 Beta Chain)
Key Component of the Phagocyte NADPH Oxidase Complex
Gene Information Card
| Symbol | CYBB |
|---|---|
| Full Name | Cytochrome B-245 Beta Chain |
| Gene Type | Protein coding |
| Chromosomal Location | Xp21.1-p11.4 |
| NCBI Gene ID | 1536 ncbi.nlm.nih.gov/gene/1536 |
| Ensembl ID | ENSG00000165168 |
| UniProt ID | P04839 |
| OMIM ID | 300481 |
| HGNC ID | 2578 |
| Aliases | CGD, CGDX, GP91-1, GP91PHOX, NOX2 |
Description
The CYBB gene encodes the beta chain of cytochrome b-245, also known as gp91phox or NOX2. This protein is the catalytic subunit of the phagocyte NADPH oxidase complex, which generates superoxide anions essential for microbial killing in neutrophils and other phagocytes. Mutations in CYBB cause X-linked chronic granulomatous disease (CGD), characterized by recurrent infections and granuloma formation.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| Chronic Granulomatous Disease, X-linked | Loss-of-function mutations in CYBB impair NADPH oxidase activity, preventing superoxide production and leading to defective pathogen killing. | ClinVar, OMIM |
| Invasive Aspergillosis, Susceptibility to | Partial or hypomorphic CYBB variants reduce but do not abolish oxidase activity, increasing susceptibility to Aspergillus infections. | ClinVar, NCBI |
| Systemic Lupus Erythematosus (SLE) | Rare CYBB polymorphisms may contribute to altered oxidative burst and immune dysregulation in SLE pathogenesis. | NCBI, OMIM |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Bone Marrow | 12.5 | High |
| Spleen | 8.3 | Medium |
| Lung | 6.1 | Medium |
| Blood (whole) | 5.4 | Medium |
| Liver | 1.2 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| HL-60 (promyeloblast) | 15.2 | High expression; inducible with DMSO differentiation |
| THP-1 (monocyte) | 10.8 | High expression; upregulated upon macrophage differentiation |
| K-562 (erythroleukemia) | 2.1 | Low expression |
| HeLa (cervical carcinoma) | 0.5 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.676C>T (p.Arg226*) | Nonsense | ~10% of CGD cases | Premature stop; loss of protein function |
| c.252G>A (p.Trp84*) | Nonsense | ~5% of CGD cases | Premature stop; loss of protein function |
| c.997C>T (p.Arg333Trp) | Missense | ~3% of CGD cases | Reduced oxidase activity; hypomorphic |
| c.1222G>A (p.Gly408Arg) | Missense | ~2% of CGD cases | Impaired flavin adenine dinucleotide (FAD) binding; loss of function |
Mutation functional classification
Loss of Function (LOF)
Nonsense, frameshift, and splice-site mutations that abolish gp91phox expression or catalytic activity, causing X-linked CGD.
Gain of Function (GOF)
Not reported for CYBB; gain-of-function variants are extremely rare and not clinically documented.
Dominant Negative (DN)
Not applicable; CYBB is X-linked, and hemizygous males express only one allele. Dominant-negative effects are not described.
View complete mutation data：
Gene Ontology (GO)
| • GO:0004601 – superoxide-generating NADPH oxidase activity | • GO:0016175 – superoxide-generating NADPH oxidase activator activity |
| • GO:0043020 – NAD(P)H oxidase complex | • GO:0006801 – superoxide metabolic process |
| • GO:0045087 – innate immune response | • GO:0005737 – cytoplasm |
| • GO:0016021 – integral component of membrane |
Pathways
• Phagosome (KEGG: hsa04145)
• Neutrophil degranulation (Reactome: R-HSA-6798695)
• NADPH oxidase assembly and activation (Reactome: R-HSA-5668541)
• Fcgamma receptor (FCGR) dependent phagocytosis (Reactome: R-HSA-2029481)
Protein Summary
The CYBB protein (gp91phox, NOX2) is a 570-amino acid transmembrane glycoprotein that forms the catalytic core of the phagocyte NADPH oxidase complex. It contains binding sites for FAD, heme, and NADPH, and transfers electrons from NADPH to molecular oxygen to generate superoxide. This protein is essential for the respiratory burst in phagocytes. Mutations lead to chronic granulomatous disease (CGD), and the protein is a target for gene therapy approaches.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| CYBB Knockout HEK293 Cell Line | EDJ-KQ17866 | Human | 1536 | Details Get a Quote |
| CYBB Knockout HCT 116 Cell Line | EDJ-KQ21113 | Human | 1536 | Details Get a Quote |
| CYBB Knockout HeLa Cell Line | EDJ-KQ53036 | Human | 1536 | Details Get a Quote |
| CYBB Knockout A-549 Cell Line | EDJ-KQ61500 | Human | 1536 | Details Get a Quote |
| CYBB Knockout HL-60 Cell Line | EDC08371 | Human | 1536 | Details Get a Quote |
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