Late ATP-dependent and Ca++-activated Steps of Dense Core Granule Exocytosis

Abstract

The secretion of neurotransmitters and peptide hormones from neuronal and endocrine cells is precisely regulated by physiological demand. At the cellular level, agonist- or depolarization-induced increases in cytoplasmic Ca++ constitute the principal trigger for the exocytotic fusion of secretory vesicles with the plasma membrane. Despite the importance of regulated fusion, a description of the essential components involved and of the Ca++-dependent reactions that are rate-limiting remains incomplete (Bajjalieh and Scheller 1995).