Neutrophil cytosol factor 4 (NCF4)

Neutrophil cytosol factor 4 (NCF4, commonly referred to as p40-phox) is a regulatory cytosolic subunit of the phagocyte NADPH oxidase (NOX2) complex, which is critical for innate immune defense. NCF4 is primarily expressed in myeloid cells and facilitates the assembly and activation of the NADPH oxidase complex by interacting with other cytosolic subunits (NCF1/p47-phox, NCF2/p67-phox) and membrane-bound components. Upon stimulation, the complex assembles at the membrane and enables electron transfer from NADPH to molecular oxygen, producing superoxide and downstream reactive oxygen species (ROS) that are essential for the destruction of pathogens by phagocytes. NCF4’s PX domain directs the complex to specific cellular compartments by binding characteristic membrane phospholipids. Mutations in NCF4 can impair ROS production, leading to increased susceptibility to infections (as seen in chronic granulomatous disease) and contribute to autoimmune and inflammatory diseases due to its role in immune regulation, particularly affecting B cell development and inflammatory responses[1][2][3][4][5].

Other names

p40-phoxp40phoxNeutrophil cytosolic factor 4Neutrophil cytosol factor 4, 40kDaNeutrophil NADPH oxidase factor 4NCF-4SH3 and PX domain-containing protein 4SH3PXD4NCF4_HUMAN

Inhibition of NADPH oxidase reduces ROS production, decreasing phagocyte microbial killing and modulating immune function[2].