Proteolysis on the cell surface and in the extracellular matrix is essential for normal cellular functions during development and in the adult, but it may also have undesirable consequences by promoting diseases such as cancer, arthritis, and Alzheimer's disease. A particularly interesting function of proteolysis on the cell surface is to release ectodomains of membrane proteins from the plasma membrane. This process, which is referred to as protein ectodomain shedding, affects a variety of proteins with important roles in development and in disease, including cytokines, growth factors, receptors, adhesion proteins and other proteins such as the amyloid precursor protein. In principle, protein ectodomain shedding can dramatically change the properties of a substrate protein. For example, membrane anchored growth factors such as transforming growth factor-alpha (TGF-alpha) are only able to activate their receptor, the epidermal growth factor receptor (EGFR), after they are shed from the plasma membrane. Inhibitor studies have implicated zinc-dependent metalloproteases in protein ectodomain shedding, and in particular a family of metalloproteases termed ADAMs (a disintegrin and metalloprotease). The main focus of my lab is to understand the role of different ADAMs in protein ectodomain shedding, and to learn about the functional consequences of protein ectodomain shedding for individual substrates.