Understanding the Proteasome

Every cell is equipped with machinery that removes proteins that are damaged and Saul Powell, PhD, is interested in knowing how this protein clean-up factory works during myocardial ischemia. The proteasome is a very large molecular structure that consists of multiple sub-units and its job is to break down or degrade proteins. The proteasome is in the nucleus   and cytoplasm of every cell and it gets its cues from s cellular substance called ubiquitin that tags a protein that needs to be degraded. From there, the proteasome swoops in to collect the protein and cuts off the ubiquitin so it can be reused. The proteasome unfolds the protein and feeds it into a catalytic chamber when it is broken down into peptides. Sometimes the peptides will be repackaged and transported back to the cell surface as HLA antigens. These antigens are important for immune system responses. Dr. Powell and his colleagues believe that the proteasome is critical to what goes on in the cell and could help explain how diseases unfold in the human body. They are finding that when proteasomes are not doing their job right, proteins can abnormally accumulate and cause damage. They are working on genetic models that increase proteasome in the cell to figure out how it works in health and in disease.