Cytochrome b-245 beta chain (CYBB) (CYBB)

The Cytochrome b-245 beta chain (CYBB), also known as gp91phox or NOX2, is the catalytic subunit of the NADPH oxidase complex, primarily expressed in phagocytic cells like neutrophils and macrophages (UniProt P04839). Its primary biological function is the generation of superoxide anions through the respiratory burst, a critical mechanism for the destruction of engulfed pathogens (NCBI Gene 1536). Mutations within the CYBB genomic locus are the most common cause of X-linked Chronic Granulomatous Disease (CGD), a condition where the immune system cannot effectively kill certain bacteria and fungi, leading to severe, recurrent infections (PubMed 31536016). In therapeutic contexts, the CYBB locus is a major target for gene therapy, where functional copies of the gene are introduced into hematopoietic stem cells to restore oxidase activity (PubMed 33093518). Additionally, because excessive NOX2-derived reactive oxygen species contribute to tissue damage, small-molecule inhibitors like Setanaxib are being explored to treat inflammatory and fibrotic diseases (PubMed 28651601).

Other names

gp91phoxNOX2Cytochrome b(558) subunit betaNADPH oxidase 2CGDp91-PHOXCYBB genomic locus

Inhibition of NADPH oxidase 2 (NOX2) enzymatic activity or lentiviral-mediated gene replacement to restore functional protein expression.