The C-terminal PDZ-ligand motif of the neuronal glycine transporter GlyT2 is required for efficient synaptic localization.
The neuronal glycine transporter 2 (GlyT2) belongs to the large SLC6 family of Na+/Cl--dependent neurotransmitter transporters. At its extreme C-terminus, GlyT2 carries a type III PDZ domain binding motif (PDZ-ligand motif), which interacts with the PDZ domain protein syntenin-1. Here, we investigated the physiological role of the GlyT2 PDZ-ligand motif by a loss-of-function approach. Inactivation of the PDZ-ligand motif did not impair the localization, glycosylation and transport function of recombinant GlyT2 expressed in HEK293T cells. However, in transfected hippocampal neurons, the synaptic localization of GlyT2 was significantly reduced upon PDZ-ligand motif inactivation. Co-localization of GlyT2 with marker proteins of excitatory and inhibitory synapses was decreased by down to 50% upon PDZ-ligand motif deletion as compared to the wild-type protein. These data indicate that the C-terminal PDZ-ligand motif of GlyT2 plays an important role in transporter trafficking to and/or stabilization at synaptic sites.
Armsen
Wencke
W
Department of Neurochemistry, Max-Planck Institute for Brain Research, Deutschordenstrasse 46, 60528 Frankfurt am Main, Germany.
Himmel
Bettina
B
Betz
Heinrich
H
Eulenburg
Volker
V
D020816:Amino Acid Motifs; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D005998:Glycine / Q000378:metabolism*; D050487:Glycine Plasma Membrane Transport Proteins / Q000378:metabolism*; D049452:Green Fluorescent Proteins; D006624:Hippocampus / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans; D051379:Mice; D008810:Mice, Inbred C57BL; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009433:Neural Inhibition / Q000502:physiology; D009474:Neurons / Q000378:metabolism* / Q000648:ultrastructure; D017434:Protein Structure, Tertiary / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D013569:Synapses / Q000378:metabolism* / Q000648:ultrastructure; D013570:Synaptic Membranes / Q000378:metabolism / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology*
D015415:Biomarkers; D050487:Glycine Plasma Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493270:Slc6a5 protein, mouse; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D005998:Glycine