The GABA transporter GAT1 and the MAGUK protein Pals1: interaction, uptake modulation, and coexpression in the brain.
GABAergic signaling in the CNS is terminated in part through uptake of GABA by GABA transporters. We used the yeast two-hybrid system to identify proteins that associate with the carboxy-terminus of the neuronal GABA transporter GAT1. We found an interaction between GAT1 and the MAGUK protein Pals1. When coexpressed in COS-7 cells, Pals1 co-immunoprecipitates with GAT1. We demonstrate cellular coexpression of GAT1 and Pals1 in the mouse hippocampus and striatum. Functionally, coexpression of GAT1 and Pals1 in COS-7 cells increases [3H]-GABA uptake by GAT1. The mechanism underlying increased uptake is increased levels of GAT1 protein. We hypothesize that Pals1 contributes to the stability of the GAT1, thus promoting the expression level of the transporter protein. In the CNS, Pals1 may stabilize GAT1 at appropriate levels in specific GABAergic neurons.
McHugh
Ellen M
EM
Neurobiology Curriculum, University of North Carolina, Chapel Hill, NC 27599, USA.
Zhu
Weiguo
W
Milgram
Sharon
S
Mager
Sela
S
D000595:Amino Acid Sequence; D000818:Animals; D001921:Brain / Q000378:metabolism*; D019556:COS Cells; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002522:Chlorocebus aethiops; D005136:Eye Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D050485:GABA Plasma Membrane Transport Proteins; D005786:Gene Expression Regulation / Q000502:physiology; D015723:Gene Library; D051528:Guanylate Kinases; D008565:Membrane Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009703:Nucleoside-Phosphate Kinase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D062725:Tight Junction Proteins; D014162:Transfection; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D002352:Carrier Proteins; D005136:Eye Proteins; D050485:GABA Plasma Membrane Transport Proteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C107903:PATJ protein, human; C493414:Slc6a1 protein, mouse; C493415:Slc6a1 protein, rat; D062725:Tight Junction Proteins; D005680:gamma-Aminobutyric Acid; D009703:Nucleoside-Phosphate Kinase; D051528:Guanylate Kinases