Modification of the cytosolic regions of GABA transporter GAT1 by calpain.
Cytosolic regions of sodium dependent neurotransmitter transporters regulate their surface density and transporting function by interconnecting themselves with intracellular signaling pathways. Here we show that calpain activation in rat brain synaptosomes leads to cleavage of both N- and C-terminal regions of GABA transporter GAT1. In the C-terminal region, calpain removes a short segment of amino acids involved in binding of GAT1 to a high-density PDZ anchoring matrix. Using a protein pull-down assay, we found that C-terminal truncation of GAT1 results in modification of its interacting proteome in vitro. Results indicate that calpain activation/inhibition in GABAergic terminals may influence the scaffolding and surface expression of GABA transporter GAT1 under normal conditions or imbalance GAT1-mediated GABAergic transmission under pathological states.
Baliova
Martina
M
Laboratory of Neurobiology, Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 84251 Bratislava, Slovakia.
Knab
Andrea
A
Franekova
Veronika
V
Jursky
Frantisek
F
D000818:Animals; D001483:Base Sequence; D015153:Blotting, Western; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002154:Calpain / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism*; D017931:DNA Primers; D004789:Enzyme Activation; D005260:Female; D050485:GABA Plasma Membrane Transport Proteins / Q000378:metabolism*; D011485:Protein Binding; D020543:Proteome; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
D017931:DNA Primers; D050485:GABA Plasma Membrane Transport Proteins; D020543:Proteome; D002154:Calpain