SELECTIVE LOCALIZATION AND REGULATED RELEASE OF CALCITONIN-GENE-RELATED PEPTIDE FROM DENSE-CORE VESICLES IN ENGINEERED PC12 CELLS

Introduction of the gene for calcitonin into the neuroendocrine PC12 c ell line resulted in the expression of the neuronal-specific splice pr oduct, calcitonin gene-related peptide (CGRP), Expression of this neur opeptide did not require treatment of the PC12 cells with NGF, By all available criteria, including biochemical, immunological, and morpholo gical analysis, we have determined that the CGRP in stably transfected PC12 cells is sorted selectively into the large, dense-core catechola mine-containing secretory vesicles, Conversely, the CORP is excluded f rom the small, synaptophysin-rich vesicles present in the same cells, Stimulation conditions that trigger the release of catecholamines caus e a parallel burst in the release of CGRP, In all these respects, the engineered PC12 cells process the foreign CGRP in a manner similar to that seen in spinal motor neurons in vivo, These results indicate that this small (37 amino acids) peptide contains sorting information suff icient for targeting to large, dense-core vesicles in heterologous cel ls, placing very narrow constraints on the possible location of sortin g signals, In addition, this CGRP-expressing cell line opens the possi bility of studying the physiological role of CGRP in the establishment and maintenance of neuromuscular contacts. (C) 1996 Wiley-Liss, Inc.