Synaptotagmin IX regulates Ca2+-dependent secretion in PC12 cells.


Journal Article

Synaptotagmin (Syt) I-deficient phaeochromocytoma (PC12) cell lines show normal Ca(2+)-dependent norepinephrine (NE) release (Shoji-Kasai, Y., Yoshida, A., Sato, K., Hoshino, T., Ogura, A., Kondo, S., Fujimoto, Y., Kuwahara, R., Kato, R., and Takahashi, M. (1992) Science 256, 1821-1823). To identify an alternative Ca(2+) sensor, we searched for other Syt isoforms in Syt I-deficient PC12 cells and identified Syt IX, an isoform closely related to Syt I, as an abundantly expressed dense-core vesicle protein. Here we show that Syt IX is required for the Ca(2+)-dependent release of NE from PC12 cells. Antibodies directed against the C2A domain of either Syt IX or Syt I inhibited Ca(2+)-dependent NE release in permeable PC12 cells indicating that both Syt proteins function in dense-core vesicle exocytosis. Our results support the idea that Syt family proteins that co-reside on secretory vesicles may function cooperatively and redundantly as potential Ca(2+) sensors for exocytosis.

Full Text

Duke Authors

Cited Authors

  • Fukuda, M; Kowalchyk, JA; Zhang, X; Martin, TFJ; Mikoshiba, K

Published Date

  • February 15, 2002

Published In

Volume / Issue

  • 277 / 7

Start / End Page

  • 4601 - 4604

PubMed ID

  • 11751925

Pubmed Central ID

  • 11751925

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.C100588200


  • eng

Conference Location

  • United States