The Small GTPase Rab17 Regulates the Surface Expression of Kainate Receptors but not AMPA Receptors in Hippocampal Neurons via Dendritic Trafficking of Syntaxin-4 [Cell Biology]

June 3rd, 2014 by Mori, Y., Fukuda, M., Henley, J. M.

Glutamate receptors are critical for excitatory synaptic transmission and plasticity. However, many of the molecular mechanisms underlying their regulation and trafficking remain elusive. We previously demonstrated that the small GTPase Rab17 regulates dendritic trafficking in hippocampal neurons. Here we investigated the role(s) of Rab17 in AMPA receptor and kainate receptor trafficking. While Rab17 knockdown did not affect surface expression of the AMPAR subunit GluA1 under basal or chemically-induced LTP conditions, it significantly reduced surface expression of the KAR subunit GluK2. Rab17 co-localizes with Syntaxin-4 in the soma, dendritic shaft, the tips of developing hippocampal neurons, and in spines. Rab17 knockdown caused Syntaxin-4 redistribution away from dendrites and into axons in developing hippocampal neurons. Syntaxin-4 knockdown reduced GluK2, but had no affect on GluA1, surface expression. Moreover, overexpression of constitutively active Rab17 promoted dendritic surface expression of GluK2 by enhancing Syntaxin-4 translocation to dendrites. These data suggest that Rab17 regulates the dendritic trafficking of Syntaxin-4 to selectively regulate dendritic surface insertion of GluK2-containing KARs in rat hippocampal neurons.
  • Posted in Journal of Biological Chemistry, Publications
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