EROS-mediated control of NOX2 and P2X7 biosynthesis

EROS (Essential for Reactive Oxygen Species) protein is indispensable for expression of the gp91 phox -p22 phox heterodimer of the phagocyte NADPH oxidase. EROS deficiency in humans causes the severe immunodeficiency, chronic granulomatous disease (CGD), but its mechanism of action remains unknown. We elucidate the role of EROS, showing it acts at the earliest stages of gp91 phox maturation. It binds the immature 58kDa gp91 phox directly, interacting with the OST glycosylation machinery and prevents gp91 phox degradation. EROS also regulates the purine receptors P2X7 and P2X1 through direct interactions and P2X7 is almost absent in EROS deficiency. Accordingly, lack of EROS results in markedly abnormal P2X7 signalling, inflammasome activation and T cell responses. The loss of both ROS and P2X7 signalling leads to resistance to influenza infection. Our work identifies EROS as a highly selective chaperone for key proteins in innate and adaptive immunity and a rheostat for immunity to infection. It has profound implications for our understanding of immune physiology, immunodeficiency and gene therapy. ### Competing Interest Statement The authors have declared no competing interest.