Cells recycle old components using a system called the proteasome. Some people are born without parts of the proteasome, and they suffer from a disease associated with inflammation. We have identified the molecular trigger for this inflammation. Our findings are also relevant for patients being treated with proteasome inhibitors. In some of these diseases, such as lupus, inflammation can be a side-effect of proteasome inhibitor therapy, and we can now reduce this and make the treatments safer.