Glycine acts as inhibitory neurotransmitter in many interneurons of the spinal cord and brain stem by activating strychnine sensitive glycine receptors and is an essential co-agonist for the NMDAR subtype of the ionotropic glutamate receptors. At both receptors, the concentration of glycine is regulated by two high- affinity Na+-dependent glycine transporters located in the plasma membranes adjacent cells. GlyT1 is widely expressed in glial cells of all major regions of the CNS, whereas GlyT2 is found in brain stem and spinal cord interneurons highly enriched in the plasma membrane of axonal boutons. Data obtained from GlyT deficient mice are consistent with glial GlyT1 catalyzing the removal of glycine from the synaptic cleft, whereas GlyT2 replenishes glycinergic nerve terminal with neurotransmitter for reloading of synaptic vesicle. The phenotype of GlyT2 KO mice resembles the symptomology of the human disease hyperekplexia. Genetic screening of human patients for mutations within the GlyT2 gene identified several mutations within this gene. Here, we find one of them to be located at the intracellular C-terminal domain close the PDZ domain binding motive of the transporter. In hippocampal neurons, the inactivation of the PDZ domain binding motive led to impaired distribution of the transporter, suggesting an important role of this motive for synaptic localization of the transporter.