Article abstract
Nature Cell Biology 3, 331 - 338 (2001)
Published online: 6 March 2001 | doi:10.1038/35070000
Phosphorylation of Snapin by PKA modulates its interaction with the SNARE complex
Milan G. Chheda1, Uri Ashery2, Pratima Thakur2, Jens Rettig2,3 & Zu-Hang Sheng1
Abstract
cAMP-dependent protein kinase A (PKA) can modulate synaptic transmission by acting directly on unknown targets in the neurotransmitter secretory machinery. Here we identify Snapin, a protein of relative molecular mass 15,000 that is implicated in neurotransmission by binding to SNAP-25, as a possible target. Deletion mutation and site-directed mutagenetic experiments pinpoint the phosphorylation site to serine 50. PKA-phosphorylation of Snapin significantly increases its binding to synaptosomal-associated protein-25 (SNAP-25). Mutation of Snapin serine 50 to aspartic acid (S50D) mimics this effect of PKA phosphorylation and enhances the association of synaptotagmin with the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Furthermore, treatment of rat hippocampal slices with nonhydrolysable cAMP analogue induces in vivo phosphorylation of Snapin and enhances the interaction of both Snapin and synaptotagmin with the SNARE complex. In adrenal chromaffin cells, overexpression of the Snapin S50D mutant leads to an increase in the number of release-competent vesicles. Our results indicate that Snapin may be a PKA target for modulating transmitter release through the cAMP-dependent signal-transduction pathway.
- Synaptic Function Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, 36 Convent Drive, Bethesda, Maryland 20892-4154, USA
- Department of Membrane Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg, 37077 Göttingen, Germany
- Current address: Physiologisches Institut, Universität des Saarlandes, 66421 Homburg, Germany
Correspondence to: Zu-Hang Sheng1 e-mail: shengz@ninds.nih.gov
