GLX-351322

Supplementary information

This supplementary information is collated from multiple sources and compiled automatically.

NADPH oxidase 4 also known as NOX4 is an enzyme that catalyzes the production of reactive oxygen species (ROS) by transferring electrons from NADPH to molecular oxygen. NOX4 has a molecular weight of approximately 67 kDa. It is expressed in various tissues including the kidneys lungs and heart with particularly high expression in vascular smooth muscle cells and endothelial cells. The protein serves as a homo- or heterodimer and is distinct due to its ability to produce hydrogen peroxide directly.

Biological function summary

NADPH oxidase 4 plays a role in cellular signaling and oxidative stress responses. The enzyme is part of the NADPH oxidase family which consists of several members each forming complexes with regulatory subunits such as p22phox NOXO1 or NOXA1. These complexes contribute to NOX4's stable and constitutive activity impacting cell growth differentiation and apoptosis processes. Its persistent activation suggests it modulates basal ROS levels acting as a control point in redox-dependent cell signaling.

Pathways

NOX4 is intricately involved in the TGF-beta signaling pathway and the regulation of endothelial nitric oxide synthase (eNOS) activity. The TGF-beta signaling involves NOX4 in fibrotic responses and cellular transformations often intersecting with other proteins like Smad3. In the nitric oxide signaling pathway interactions with eNOS affect the bioavailability of nitric oxide impacting vascular function. These relationships indicate NOX4's role in managing oxidative stress and maintaining vascular homeostasis through specific signaling cascades involving these proteins.

NADPH oxidase 4 contributes significantly to the pathogenesis of idiopathic pulmonary fibrosis and atherosclerosis. In idiopathic pulmonary fibrosis excessive ROS production by NOX4 leads to fibroblast differentiation and tissue remodeling. NOX4's involvement in atherosclerosis relates to overproduction of vascular ROS which affects endothelial function and promotes inflammatory processes. The protein's interaction with TGF-beta in fibrosis and eNOS in vascular disorders emphasizes its role in influencing disease progression through pathways linked to oxidative damage.