V-1, a catecholamine biosynthesis regulatory protein, positively controls catecholamine secretion in PC12D cells

Stably transfected PC12D cell lines overexpressing a catecholamine biosynthesis regulatory protein, V-1, were used to examine the functional role of V-1 in catecholamine secretion. High K+-induced dopamine secretion in V-1 overexpressing clones was shown to be markedly potentiated compared with control clones carried with a vector alone. As assayed intracellular calcium concentration ([Ca2+]i) using fura-PE3, V-1 overexpression was observed to enhance high K+-elicited [Ca2+] i elevation. Electron microscopic analysis revealed an increase in dense-cored vesicle formation by V-1 overexpression. These results suggest that the enhancement of high K+-induced dopamine secretion by V-1 overexpression results from the potentiation of high K+-induced [Ca2+]i elevation and the increase in the number of dense-cored vesicles. (C) 2002 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.