Last Saturday, Denis Belitškin defended his Ph.D. thesis. The topic was The role of type II serine protease hepsin in breast cancer signaling. I thoroughly enjoyed the discussion with the opponent Karin List, which happened over Zoom with only a small real-life audience. Proteases have slowly become one of my favorite protein classes. In the old days, they mostly were appreciated for their degradation function, but it is meanwhile clear that they are much more complex. My own interest is their role in the activation of signaling molecules. In this context, proteases are signaling molecules, playing at the same level as hormones, cytokines, and growth factors. Thanks, Denis for a convincing performance and the karonkka!