Cyclic AMP potentiates Ca-dependent exocytosis in pancreatic duct epithelial cells

Eukaryotic cells discharge secretory products by fusion of secretory vesicles with the plasma membrane, a process that is often regulated. In neurons and endocrine cells, exocytosis uses intracellular Ca as the final trigger and can be enhanced in different ways by protein kinases. Thus, in pituitary gonadotropes, protein kinase C (PKC) increases the Ca sensitivity of exocytosis (Zhu et al., 2002; Yang et al., 2005), whereas in insulin-secreting  cells and in adrenal chromaffin cells, cyclic AMP (cAMP)–dependent protein kinase (PKA) and PKC augment the size of the readily releasable pool of secretory vesicles (Gillis et al., 1996; Nagy et al., 2004; Wan et al., 2004; Yang and Gillis, 2004).