A protease is an enzyme that can split a protein into peptides. Alterations in normal protease expression are known to be involved in the development of cancer, arthritis and various lung, neurological and cardiovascular diseases. As a result, many proteases and their substrates are an important focus of attention as potential drug targets. Among proteases, matrix metalloproteases (MMPs) are responsible for the proteolytic modification of the extracellular matrix, a complex network of polysaccharides and proteins secreted by cells that serves as a structural element in tissues and also influences their development and physiology. While more is being learned about the multiple functions of MMPs –, many of which are beneficial – their roles and biological functions are not fully understood. David Rodriguez’s research seeks to unravel the complex web of connections among MMPs, their natural substrates, inhibitors and other proteases. He is using a technique known as Mass Spectrometry to detect and identify hundreds, even thousands, of proteins in a sample. By identifying and describing the complex set of signaling pathways in which MMPs are involved, Rodriguez is hoping to better understand the role of these proteases and to predict the consequences when they function abnormally. Such knowledge is critical for designing more effective drugs to treat diseases which result from abnormal protease function.