Maintenance of the reactive oxygen species (ROS) homeostasis is essential to preserve cell integrity and is thus vital for the survival and growth of almost all life. In mammals, ROS are actively generated outside of the cell or near the cell membrane to protect against invading pathogens, transduce cell signaling, facilitate hormone biosynthesis, and maintain the cardiac rhythm. On the other hand, excessive ROS production is associated with protein and DNA damage, causes oxidative stress, and leads to the development of many chronic conditions, such as aging, cancer, diabetes, neurodegenerative diseases and cardiac disorders. Thus, targeting the NADPH oxidases is an attractive strategy for combatting numerous diseases associated with redox stress.
The NADPH oxidases, the only enzyme family in humans whose primary function is to mediate cross-membrane electron transfer and produce ROS, play a vital role in maintaining redox homeostasis. Human encodes seven NADPH oxidases (NOXs), NOX1-5 and DUOX1-2. Different NOXs share similar catalytic cores but have distinct activation and regulatory mechanisms. Understanding the molecular mechanisms underlying NOX activation and regulation paves the way for developing therapeutic tools for treating ROS-associated diseases.
The first structure of a mammalian NADPH oxidase complex: DUOX1-DUOXA1
DUOX1 is one of the seven mammalian NADPH oxidase members, catalyzes the production of hydrogen peroxide (H2O2), and plays a crucial role in innate host defense and thyroid hormone biosynthesis. Our lab determined the first high-resolution cryoEM structures of mouse DUOX1 in a complex with its maturation factor, DUOXA1.
revealed the overall architecture of a mammalian NADPH oxidase
uncovered the substrate binding pocket
illustrated the electron transfer path of an NADPH oxidase
suggested a protein-oligomerization-dependent regulation of DUOX1