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Subcellular Localization of the Neuronal Glycine Transporter GLYT2 in Brainstem
Author(s) -
Núñez Enrique,
PérezSiles Gonzalo,
Rodenstein Lara,
AlonsoTorres Pablo,
Zafra Francisco,
Jiménez Esperanza,
Aragón Carmen,
LópezCorcuera Beatriz
Publication year - 2009
Publication title -
traffic
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.677
H-Index - 130
eISSN - 1600-0854
pISSN - 1398-9219
DOI - 10.1111/j.1600-0854.2009.00911.x
Subject(s) - biology , endosome , synaptic vesicle , microbiology and biotechnology , neurotransmitter transporter , glycine receptor , vesicular transport protein , vesicle , biochemistry , intracellular , neurotransmitter , glycine , amino acid , receptor , membrane
The neuronal glycine transporter GLYT2 belongs to the neurotransmitter:sodium:symporter (NSS) family and removes glycine from the synaptic cleft, thereby aiding the termination of the glycinergic signal and achieving the reloading of the presynaptic terminal. The task fulfilled by this transporter is fine tuned by regulating both transport activity and intracellular trafficking. Different stimuli such as neuronal activity or protein kinase C (PKC) activation can control GLYT2 surface levels although the intracellular compartments where GLYT2 resides are largely unknown. Here, by biochemical and immunological techniques in combination with electron and confocal microscopy, we have investigated the subcellular distribution of GLYT2 in rat brainstem tissue, and characterized the vesicles that contain the transporter. GLYT2 is shown to be present in small and larger vesicles that contain the synaptic vesicle protein synaptophysin, the recycling endosome small GTPase Rab11, and in the larger vesicle population, the vesicular inhibitory amino acid transporter VIAAT. Rab5A, the GABA transporter GAT1, synaptotagmin2 and synaptobrevin2 (VAMP2) were not present. Coexpression of a Rab11 dominant negative mutant with recombinant GLYT2 impaired transporter trafficking and glycine transport. Dual immunogold labeling of brainstem synaptosomes showed a very close proximity of GLYT2 and Rab11. Therefore, the intracellular GLYT2 resides in a subset of endosomal membranes and may traffic around several compartments, mainly Rab11‐positive endosomes.