NOX4 is an NADPH oxidase that generates superoxide within the cell. It is primarily found in vascular cells, fibroblasts, and osteoclasts, with abundant expression in the kidney. Unlike its family members NOX1 and NOX2, NOX4 is constitutively active, producing primarily H2O2 rather than O2. This different species generated triggers NOX4-specific actions in downstream cell signaling.
