RGD Reference Report - Synaptotagmin IV regulates glial glutamate release. - Rat Genome Database

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Synaptotagmin IV regulates glial glutamate release.

Authors: Zhang, Q  Fukuda, M  Van Bockstaele, E  Pascual, O  Haydon, PG 
Citation: Zhang Q, etal., Proc Natl Acad Sci U S A. 2004 Jun 22;101(25):9441-6. Epub 2004 Jun 14.
RGD ID: 11535103
Pubmed: (View Article at PubMed) PMID:15197251
DOI: Full-text: DOI:10.1073/pnas.0401960101

Calcium-binding synaptotagmins (Syts) are membrane proteins that are conserved from nematode to human. Fifteen Syts (Syts I-XV) have been identified in mammalian species. Syt I has been well studied and is a candidate for the Ca(2+)-sensor that triggers evoked exocytosis underlying fast synaptic transmission. Whereas the functions of the other Syts are unclear, Syt IV is of particular interest because it is rapidly up-regulated after chronic depolarization or seizures, and because null mutations exhibit deficits in fine motor coordination and hippocampus-dependent memory. Screening Syts I-XIII, which are enriched in brain, we find that Syt IV is located in processes of astroglia in situ. Reduction of Syt IV in astrocytes by RNA interference decreases Ca(2+)-dependent glutamate release, a gliotransmission pathway that regulates synaptic transmission. Mutants of the C2B domain, the only putative Ca(2+)-binding domain in Syt IV, act in a dominant-negative fashion over Ca(2+)-regulated glial glutamate release, but not gliotransmission induced by changes in osmolarity. Because we find that Syt IV is expressed predominantly by astrocytes and is not in the presynaptic terminals of the hippocampus, and because Syt IV knockout mice exhibit hippocampal-based memory deficits, our data raise the intriguing possibility that Syt IV-mediated gliotransmission contributes to hippocampal-based memory.

Gene Ontology Annotations    

Cellular Component

Objects Annotated

Genes (Rattus norvegicus)
Syt4  (synaptotagmin 4)

Additional Information