Dr. Castle has devoted his scientific career to elucidating the mechanism of secretion from exocrine cells, in particular salivary glands, and throughout his career he has made many novel and important contributions that have had a highly significant impact on our understanding of the molecular mechanisms of exocytosis. These include analysis of secretory granules and their membrane components; demonstration of a proton pump in secretion granules, the role of pH in aggregation of protein in the granules as well as removal of other ions in condensation of granule content, and salivary-gland-specific proline-rich proteins that play a role for their sorting into secretion granules. These studies have led to the more general conclusion that there is no common module in secreted proteins that ensure their sorting into secretion granules, and that this process therefore is of a passive nature.
In recent years, there has been intense interest in membrane trafficking in the cell and the process whereby the fusion of secretion granules and cell membranes occurs, and proteins such as v-SNAREs and t-SNAREs have been identified. Dr. Castle has contributed significantly to this field with his discovery of a new family of proteins--named SCAMPs--occurring widespread in different mammalian tissues that may be important in a late step in exocytosis.
Dr. Castle is also responsible for demonstrating a total of four pathways of secretion in parotid cells--the constitu
Contact: Linda T. Hemphill
International & American Association for Dental Research