Rebekka Schairer from Prof. Thome’s lab just published an article in PNAS, which provides new molecular insights into the mechanisms of lymphocyte activation and lymphoma development. The report identifies the Ig3 domain of the protease MALT1 as a novel ubiquitin-binding domain that promotes MALT1 activation by monoubiquitination, through an allosteric mechanism. Since MALT1 protease activity is critical for the activation and proliferation of lymphocytes, these findings provide insight into the regulation of MALT1 activity that could be of therapeutic interest for immunomodulation.