Zhijian "James" Chen’s research into complex cellular biochemistry has led to the discovery of pathways and proteins that trigger immune and stress responses. Chen has identified proteins, such as the mitochondrial protein MAVS, that are crucial to the body’s defense against RNA viruses such as influenza and Ebola. Now, Chen and his team are dissecting a signaling pathway involving a novel DNA sensor – cyclic GMP-AMP (cGAMP) synthase, or cGAS – which activates an interferon response that may play a role in immune defense against pathogens and malignant cells, as well as in autoimmune diseases such as lupus. Treatment of these autoimmune diseases could involve chemical inhibition of cGAS, whereas cGAMP and its derivatives may be used as adjuvants for vaccines and cancer immunotherapies.