Pictorial representation of p22^phox.

The shaded areas represent the putative transmembrane regions. The N-terminus and C-terminus are both cytoplasmic. The stippled area is the proline-rich sequence (amino acids 151-160) that mediates a protein/protein interaction with p47^phox. Note that all missense mutations that result in the complete loss of protein (the A22° phenotype) are located within the transmembrane regions, whereas the mutation causing the A22⁺ phenotype, as well as the polymorphic amino acids, are located outside the membrane.