Silence of synaptotagmin I in INS-1 cells inhibits fast exocytosis and fast endocytosis
- Institute of Biophysics and Biochemistry, HuaZhong University of Science and Technology, Wuhan 430074 (China)
- Institute of Biophysics and Biochemistry, HuaZhong University of Science and Technology, Wuhan 430074 (China) and National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101 (China)
Synaptotagmin I (Syt I) is a Ca{sup 2+} sensor for triggering fast synchronized release of neurotransmitters. However, controversy remains whether Syt I is also obligatory for the exocytosis and endocytosis of larger dense core vesicles (LDCVs) in endocrine cells. In this study, we used a short hairpin RNA (shRNA) to silence the expression of Syt I and investigated the roles of Syt I on exocytosis and endocytosis in INS-1 cells. Our results demonstrated that expression of Syt I is remarkably reduced by the Syt I gene targeting shRNA. Using high-time resolution capacitance measurement, we found that the silence of Syt I decreased the calcium sensitivity of fusion of insulin granules and therefore reduced the exocytotic burst triggered by step-like [Ca{sup 2+}] {sub i} elevation. In addition, the occurrence frequency and amplitude of fast endocytosis were remarkably reduced in the silenced cells. We conclude that Syt I not only participates in the Ca{sup 2+}-sensing of LDCV fusion with plasmalemma, but also plays a crucial role in fast endocytosis in INS-1 cells.
- OSTI ID:
- 20854411
- Journal Information:
- Biochemical and Biophysical Research Communications, Vol. 347, Issue 1; Other Information: DOI: 10.1016/j.bbrc.2006.06.045; PII: S0006-291X(06)01337-4; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0006-291X
- Country of Publication:
- United States
- Language:
- English
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