Table 1.

The activity, regulation and expression of the main NOXs in the cardiovascular system

	NOX1	NOX2	NOX4	NOX5
Constitutive activity	Absent or very low	Absent or very low	High	Low
Requirement for p22phox	Yes	Yes	Yes	No
Essential regulatory subunits	NOXO1, NOXA1, Rac	p67phox, p47phox, p40phox, Rac	None	None
Control	Post-translational modifications of regulatory subunits	Post-translational modifications of regulatory subunits	Transcriptional. Can be regulated by Poldip2	Calcium binding
Cell expression	Vascular smooth muscle, possibly endothelial cells	Endothelial cells, cardiomyocytes, fibroblasts, human vascular smooth muscle, inflammatory cells	Endothelial cells, cardiomyocytes, fibroblasts, vascular smooth muscle cells	Human endothelium, human vascular smooth muscle