Remarkable roles of proteolysis on and beyond the cell surface

Proteolysis on the cell surface and in the extracellular matrix is essentia l for normal cellular functions during development and in the adult, but it may also have undesirable consequences, such as promoting cancer, arthriti s, and Alzheimer's disease. Recent advances highlight the roles of zinc-dep endent metalloproteinases (metzincins) in proper skeletal development, in a ctivating EG F-receptor ligands, in Notch-dependent signaling, and in initi ating and promoting tumorigenesis.