Vesicular reuptake inhibition by a synaptotagmin I C2B domain antibody at the squid giant synapse

Rodolfo R. Llinás, Mutsuyuki Sugimori, Kimberly A. Moran, Jorge E. Moreira, Mitsunori Fukuda

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


Synaptotagmin (Syt) I, a ubiquitous synaptic vesicle protein, comprises a transmembrane region and two C2 domains. The C2 domains, which have been shown to be essential for both synaptic vesicle exocytosis and endocytosis, are also seen as the Ca2+ sensors in synaptic vesicular release. In a previous study, we reported that a polyclonal antibody raised against the squid (Loligo pealei) Syt I C2B domain, while inhibiting vesicular endocytosis, was synaptic release neutral at the squid giant synapse. Recent reports concerning the C2B requirements for synaptic release prompted us to readdress the role of C2B in squid giant synapse function. Presynaptic injection of another anti-Syt I-C2B antibody (using recombinant whole C2B domain expressed in mammalian cell culture as an antigen) into the presynaptic terminal reproduced our previous results, i.e., reduction of vesicular endocytosis without affecting synaptic release. This set of results addresses the issue of the geometrical arrangement of the Ca2+ sensor, allowing the C2B domain antibody to restrict Ca 2+-dependent C2B self-oligomerization without modifying the Ca 2+-dependent release process.

Original languageEnglish
Pages (from-to)17855-17860
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number51
Publication statusPublished - 2004 Dec 21
Externally publishedYes


  • Mollusk
  • Presynaptic
  • Synaptic transmission

ASJC Scopus subject areas

  • General


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