Peter Lyons (Biology)
The role of carboxypeptidase O in cell adhesion and migration
Proteases are found ubiquitously and are involved in a multitude of physiological reactions, from digestion of dietary proteins to regulation of complex signaling cascades. Many proteases modify substrates through removal of large domains. In other cases, however, the removal of a single amino acid dramatically alters the function of a protein or peptide. The metallocarboxypeptidase (CP) family is a major class of enzymes that removes single amino acids from the C-termini of a diverse array of substrates, from neuropeptides to dietary proteins. While CPs involved in digestion have been investigated for more than 80 years, little is known about the many other CPs and their protein and peptide substrates.
Recently, a newly discovered CP, carboxypeptidase O (CPO), was characterized and predicted to play a role in dietary protein digestion within the intestinal tract. CPO was found to be a membranebound enzyme unique in its structure and substrate specificity. Significantly, recent unpublished investigations have indicated that CPO may be involved in controlling the migratory and adhesive properties of intestinal enterocytes in addition to digesting food. The studies proposed herein aim to further investigate this non-digestive role of CPO through cell culture and biochemical approaches. It is proposed that CPO may play a role in regulating the development of colorectal cancer through specific proteolysis, and the studies proposed will go a long way toward discovering these substrate proteins and further characterizing the molecular and cellular function of CPO.