Regulation of synaptic vesicle recycling by calcineurin in different vesicle pools

Susumu Kumashiro, Yun Fei Lu, Kazuhito Tomizawa, Masayuki Matsushita, Fan Yan Wei, Hideki Matsui

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


The synaptic vesicles keep recycling by the processes of endocytosis and exocytosis to maintain the normal synaptic transmission. The synaptic vesicles are classified as the readily releasable pool (RRP) and the reserve pool (RP). In the endocytosis process, calcineurin (CaN), a Ca2+/calmodulin- dependent protein phosphatase, has been shown to play important roles. However, it is unclear about its roles in different vesicle pools. Here, we investigated the role of CaN in the regulation of vesicle recycling in the RRP and RP. Vesicle recycling was monitored by using fluorescent dyes FM1-43 and FM4-64 in the primary cultures of hippocampal neurons. Inhibition of CaN by FK506 and cyclosporin A suppressed the endocytosis in the RP, but not in the RRP. Inhibition of CaN also restrained the exocytic process triggered by 10 Hz stimulation, but had no effect on 3-5 Hz stimulation-induced exocytosis. FK506 also reduced the total vesicle pool size in the synaptic terminals. A synthesized CaN inhibitory peptide showed the similar effects as FK506 and cyclosporin A. These results revealed a novel mechanism that CaN plays critical roles in the distinct vesicle recycling processes.

Original languageEnglish
Pages (from-to)435-443
Number of pages9
JournalNeuroscience Research
Issue number4
Publication statusPublished - 2005 Apr


  • Calcineurin
  • Endocytosis
  • Exocytosis
  • Readily releasable pool
  • Reserve pool
  • Synaptic vesicle


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