The interests of Professor Castellino's laboratory involve the structure, function and activation of proteins that participate in blood coagulation and blood clot dissolution. The in vivo mechanisms of the roles of these proteins in these processes are being addressed through in vivo targeted gene-replacement approaches and corresponding in vitro structure-function studies on these genes and proteins are being studied by the most modern biophysical techniques, e.g., X-ray crystallography, NMR, etc. Most of these proteins exist in an inactive state in plasma and thus must be activated to enzymes to exhibit their functional properties. The molecular events involved in the activation and analysis of the concomitant structural changes that occur in the protein are investigated by modern biochemical techniques. Major tools of the laboratory involve cloning, mutagenesis and expression of variant recombinant proteins and individual protein domains, immunochemical studies of the proteins, as well as physical and chemical analysis of their solution structures. The properties of the proteins are then related to their functions. Another project receiving attention involves the structure-function relationships of small gamma-carboxyglutamic acid (Gla)-containing peptides from marine cone snails that target the brain NMDA receptor. These peptides inhibit the flow of calcium into neuronal cells, this latter event being responsible for the neuropathology associated with stroke, epilepsy, Alzheimer's Disease, ALS, etc. The biochemical, pharmacological and neurobiological mechanisms of the actions of these peptides are under study. Peptide synthesis, receptor binding, molecular biological and electrophysiological tools are currently employed in this work. To determine the biological functions of genes encoding coagulation and clot-dissolving proteins in hemostasis, cancer, inflammation, wound healing, embryonic implantation and development, metastases, and athersclerosis, gene deletion and other gene targeting experiments are being performed in mice, in conjunction with phenotyping of these animals. Such studies are expected to provide important information on the development and progression of these disease states.