PUBLICATION

Synaptotagmin-12, a synaptic vesicle phosphoprotein that modulates spontaneous neurotransmitter release

Authors
Maximov, A., Shin, O.H., Liu, X., and Südhof, T.C.
ID
ZDB-PUB-090527-1
Date
2007
Source
The Journal of cell biology   176(1): 113-24 (Journal)
Registered Authors
Keywords
none
MeSH Terms
  • Phosphorylation/drug effects
  • Calcium/metabolism
  • Animals
  • Cyclic AMP-Dependent Protein Kinases/metabolism
  • Cyclic AMP/pharmacology
  • Amino Acid Sequence
  • Hippocampus/drug effects
  • Hippocampus/ultrastructure
  • Molecular Sequence Data
  • Phosphoserine/metabolism
  • Phosphoproteins/metabolism*
  • Neurotransmitter Agents
  • Protein Transport/drug effects
  • Glycosylation/drug effects
  • Synaptotagmins/chemistry
  • Synaptotagmins/genetics
  • Synaptotagmins/metabolism*
  • Protein Binding/drug effects
  • Gene Expression Profiling
  • Rats
  • Phospholipids/metabolism
  • Mice
  • Synaptic Vesicles/drug effects
  • Synaptic Vesicles/metabolism*
  • Synaptotagmin I/metabolism
  • Inhibitory Postsynaptic Potentials/drug effects
PubMed
17190793 Full text @ J. Cell Biol.
Abstract
Central synapses exhibit spontaneous neurotransmitter release that is selectively regulated by cAMP-dependent protein kinase A (PKA). We now show that synaptic vesicles contain synaptotagmin-12, a synaptotagmin isoform that differs from classical synaptotagmins in that it does not bind Ca(2+). In synaptic vesicles, synaptotagmin-12 forms a complex with synaptotagmin-1 that prevents synaptotagmin-1 from interacting with SNARE complexes. We demonstrate that synaptotagmin-12 is phosphorylated by cAMP-dependent PKA on serine(97), and show that expression of synaptotagmin-12 in neurons increases spontaneous neurotransmitter release by approximately threefold, but has no effect on evoked release. Replacing serine(97) by alanine abolishes synaptotagmin-12 phosphorylation and blocks its effect on spontaneous release. Our data suggest that spontaneous synaptic-vesicle exocytosis is selectively modulated by a Ca(2+)-independent synaptotagmin isoform, synaptotagmin-12, which is controlled by cAMP-dependent phosphorylation.
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