METABOLISM AND TRAFFICKING OF N-TYPE VOLTAGE-OPERATED CALCIUM CHANNELS IN NEUROSECRETORY-CELLS

The N-type voltage-operated calcium channel has been characterized ove r the years as a high-threshold channel, with variable inactivation ki netics, and a unique ability to bind with high affinity and specificit y omega-conotoxin GVIA and related toxins. This channel is particularl y expressed in some neurons and endocrine cells, where it participates in several calcium-dependent processes, including secretion. omega-co notoxin GVIA was instrumental not only for the biophysical and pharmac ological characterization of N-type channels but also for the developm ent of in vitro assays for studying N-type VOCC subcellular localizati on, biosynthesis, turnover, as well as short-and long-term regulation of its expression. We here summarize our studies on N-type VOCC expres sion in neurosecretory cells, with a major emphasis on recent data dem onstrating the presence of N-type channels in intracellular secretory organelles and their recruitment to the cell surface during regulated exocytosis.