Enables superoxide-generating NADPH oxidase activator activity. Acts upstream of or within several processes, including cellular defense response; hydrogen peroxide biosynthetic process; and neutrophil-mediated killing of symbiont cell. Located in cytoplasm and membrane. Is expressed in several structures, including alimentary system; brain; hemolymphoid system; integumental system; and sensory organ. Used to study chronic granulomatous disease. Human ortholog(s) of this gene implicated in Williams-Beuren syndrome; autosomal recessive chronic granulomatous disease cytochrome b-positive type I; and chronic granulomatous disease. Orthologous to several human genes including NCF1 (neutrophil cytosolic factor 1). [provided by Alliance of Genome Resources, Apr 2022]