Constitutive NADPH oxidase which generates superoxide intracellularly upon formation of a complex with CYBA/p22phox. Regulates signaling cascades probably through phosphatases inhibition. May function as an oxygen sensor regulating the KCNK3/TASK-1 potassium channel and HIF1A activity. May regulate insulin signaling cascade. May play a role in apoptosis, bone resorption and lipolysaccharide-mediated activation of NFKB. Activated by insulin. Inhibited by diphenylene iodonium. Inhibited by plumbagin. Activated by phorbol 12-myristate 13-acetate (PMA) (By similarity). Interacts with TLR4 (By similarity). Interacts with, relocalizes and stabilizes CYBA/p22phox. Interacts with protein disulfide isomerase. Interacts with PPP1R15A (By similarity). May localize to plasma membrane and focal adhesions. Expressed in vascular smooth muscle. Up-regulated in diabetic kidney (at protein level). N-glycosylation is required for the function.